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SUPPLEMENTTO

The London GazetteOf Tuesday, the loth of September, 1946

byRegistered as a newspaper

WEDNESDAY, n SEPTEMBER, 1946

The Air Ministry,September, 1946.

THE BATTLE OF BRITAIN.The following despatch was submitted to the

Secretary of State for Air on August 20th,1941, by Air Chief Marshal Sir Hugh C. T.Dowding, G.C.B., G.C.V.O., C.M.G.,A.D.Cs, Air Officer Commanding-in-Chiej,Fighter Command, Royal Air Force.

PREAMBLE.1. I have been instructed by the Air Council

to write a Despatch on the Air Fighting oflast Autumn, which has become known as the'" Battle of Britain." JThe conditions are alittle unusual -because, firstly, the Battle endedmany months ago, secondly, a popular accountof the fighting has already been written andpublished, and, thirdly, recommendations forMention in Despatches have already beensubmitted.

2. I have endeavoured, therefore, to write areport which will, I hope, be of Historicalinterest, and which will, in any case, containthe results of more than four years' experienceof the Fighter Command in peace and war.

August 20, 1941.

THE BATTLE OF BRITAIN.PART I.—PRELIMINARY.

3. In giving an account of the Ba'ttle ofBritain it is .perhaps advisable to begin jby adefinition of my conception of the meaning ofthe phrase. The Battle may be said to havestarted when the Germans had disposed of theFrench resistance in the Summer of 1940, andturned their attention to this country.

4. The essence of their Strategy was so toweaken our Fighter Defences that their AirArm should be able to give -adequate supportto an attempted invasion of the British Isles.

Experiences in Holland and Belgium hadshown what they could do with armouredforces operating in conjunction with an AirArm which had substantially achieved the- com-mand of the Air.

5. This air supremacy was doubly necessaryto them in attacking England ibecause the bulkof their troops and war material must neces-sarily 'be conveyed by sea, and, in order toachieve success, they must be capable of givingair protection to the passage and the landingof troops and material.

6. The destruction or paralysis of the FighterCommand was therefore an essential pre-requisite to the invasion of these Islands.

7. Their immediate objectives might be Con-voys, Radio-Location Stations, Fighter Aero-dromes, Seaports, Aircraft Factories, or Londonitself. Always the underlying object was tobring the Fighter Command continuously tobattle, and to weaken its material resources andIntelligence facilities.

8. Long after the policy of " crashingthrough " with heavy bomber formations hadbeen abandoned owing to the shattering lossesincurred, the battle went on. Large fighterformations were sent over, a proportion of thefighters being adapted to carry bombs,, in orderthat the attacks might not be ignorable.

9. This last phase was perhaps the most diffi-cult to deal with tactically. It will be discussedin greater detail later on.

10. Night attacks by Heavy Bombers werecontinuous throughout the operations, and,although they persisted and increased in in-tensity as Day Bombing became more and moreexpensive, they had an essentially different pur-pose, and the " Battle of Britain " may be saidto have ended when the Fighter and Fighter-Bomber raids died down.

4544 SUPPLEMENT TO THE LONDON GAZETTE, n SEPTEMBER, 1946

11. It is difficult to fix the exact date onwhich the " Battle of Britain " can be saidto have begun. Operations of various kindsmerged into one another almost insensibly, andthere are grounds for choosing the date of the8th August, on which was made the first attackin force against laid objectives in this country,as the beginning of the Battle.

12. On the other hand, the heavy attacksmade against our Channel convoys probablyconstituted, in fact, the beginning of the Germanoffensive; because the weight and scale of theattack indicates that the primary object wasrather to bring our Fighters to battle than todestroy the hulls and cargoes of the small shipsengaged in the coastal trade. While we werefighting in Belgium and France, we suffered thedisadvantage that even the temporary stoppageof an engine involved the loss of pilot and air-craft, whereas, in similar circumstances, theGerman pilot might be fighting again the sameday, and his aircraft be airborne again in amatter of hours.

13. In fighting over England these considera-tions were reversed, and the moral and materialdisadvantages of fighting over enemy countrymay well have determined the Germans to openthe attack with a phase of fighting in which theadvantages were more evenly balanced. I havetherefore, somewhat arbitrarily, chosen theevents of the loth July as the opening of theBattle. Although many attacks had previouslybeen made on convoys, and even on land objec-tives such as Portland, the loth July saw theemployment by the Germans of the first reallybig formation (70 aircraft) intended primarilyto bring our Fighter Defence to battle on alarge scale.

14. I had 59 squadrons in various stages ofefficiency. A list of these units, with supple-mentary information, is given in Appendix A.Many of them were still suffering from theeffects of the fighting in Holland and Flanders,at Dunkerque, and during the subsequentoperations in France. Others were in processof formation and training. But, if the lessonsof the Battle are to be correctly appreciated,due consideration must be given to the factorsleading up to the situation existing when itbegan. Leaving out of account peace-timepreparations and training, the Battle of Britainbegan for me in the Autumn of 1939.

15. The first major problem arose during thediscussion of the question of sending FighterSquadrons to France. The decisive factor wasthat of Supply. Our output at the beginningof the war was about 2 Hurricanes and 2 Spit-fires per diem; and, although there were hopesof increasing Hurricane production, there wasthen no hope that Spitfire production would bematerially increased for about a year. It is truethat certain optimistic estimates had been made,but there were reasons to believe that thesecould not be implemented. At that time, wein England were out of range of GermanFighters, and I had good hopes that unescortedbomb raids on this country could be met anddefeated with a very small loss in Fighters; butthere could be no illusions concerning thewastage which would occur if we came upagainst the German Fighters in France.

16. I therefore regarded with some appre-hension the general policy of sending HomeDefence Fighter Units to France; but, as it was

clear that such an attitude was politically un-tenable, I wrote on the i6th September, 1939,a letter to the Air Ministry. In this letter Ipointed out that the Air Staff Estimate of thenumber of Fighter Squadrons necessary for thedefence of this country was 52, and that on theoutbreak of war I had the equivalent of 34(allowing for the fact that some AuxiliarySquadrons were only partially trained andequipped).

17. I wanted 12 new squadrons, 'but askedthat 8 should be raised immediately, and madeproposals for their location and employment.In a letter dated the 2ist September the AirMinistry regretted that the most they could dotowards meeting my requirements was to form2 new squadrons and 2 operational trainingunits. I was invited to a meeting of the AirCouncil on the 26th September,

18. On the 25th September I wrote expressingmy disappointment and asking for a recon-sideration. As a result of this letter, the AirCouncil Meeting, and a further meeting underthe Chairmanship of the Deputy Chief of AirStaff, the Air Ministry wrote on the gth Octobersanctioning the immediate formation of 8 newsquadrons, though 6 of these could be formedinitially only as half-squadrons owing to short-age of resources. This correspondence is toolengthy to reproduce here, but it deals alsowith my apprehensions concerning Hurricanewastage in France, which were realised in theSpring of 1940. It also dealt with an estimateworked out by the Air Ministry OrganisationStaff that after 3 months of fighting we mightexpect the Fighter strength to have been re-duced to 26 squadrons.

19. In October, 1939, the Air Ministry furtherreconsidered their policy, and ordered the for-mation of 10 additional Fighter Squadrons, 4 ofwhich were destined for the Coastal Command.

20. In January, 1940, the Northern flank ofour continuous Defence organisation was on theForth, and the South-Western flank was atTangmere in Sussex (with the exception of anisolated station at Filton for .the local defenceof Bristol and the mouth of the Severn). Onthe 2nd and 4th February I wrote two letterspointing out these limitations, and asking foran extension of Aerodrome facilities, Intelli-gence cover and communications.

21. On the 9th February I was told that apaper was in preparation, and that I would begiven an opportunity to remark on the pro-posals at a later stage.

22. On the i6th March I received the paperreferred to and forwarded my comments on the23rd March.

23. On the 8th May I received a lefttersaying that a reply had been delayed. Theproposals were now approved, and decisionswould shortly be taken.

24. This delay was presumably unavoidable,but the result was that the organisation anddevelopment of the defences of the South andWest of England were very incomplete whenthey were called upon to withstand the attackswhich the German occupation of French aero-dromes made possible.

25. The fighting in Norway has only anindirect bearing on this paper. Certain use-ful tactical lessons were gamed, particularlywith regard to deflection shooting, and I trust

SUPPLEMENT TO THE LONDON GAZETTE, 11 SEPTEMBER, 1946 4545

that the story of the epic fight of No. 263Squadron under Squadron-Leader J. W.Donaldson, D.S.O., near Andalsnes, may notbe lost to History.

26. The outcome, as it affects this account,was the virtual loss of 2 squadrons in thesinking of the •Aircraft Carrier Glorious afterthe evacuation of Narvik.

27. Next came the invasion of Holland, andthe call to send Fighters to the assistance ofthe Dutch. The distance to 'Rotterdam wasabout the extreme range of . the single-seaterFighter, which therefore operated under thedisadvantage of having a very, brief .potentialcombat-time, followed by the necessity of along sea crossing on the homeward way. TheBlenheims, of course, had the necessary en-durance, but they had not been designed asfighters, and their use against day fightersproved costly in comparison with the limitedsuccess which they attained.

28. The iDefiants were used here for the firsttime, and, although they proved very effectiveagainst unescorted bombers, they, too, .suffered•heavy casualties when they encountered fightersin strength. As the result of this experience Iformed the opinion that the Blenheims shouldbe kept exclusively for night fighting, if pos-sible, while I retained an open mind aboutthe Defiants pending some experience of short-range fighting.

29. Then began the fighting in Belgium andNorthern France, and at once my fears aboutthe incidence of wastage in this type of fightingbegan to be realised.

30. At the beginning of April, 1940, therewere 6 Fighter Squadrons in France.

31. Then 4 more complete squadrons weresent when the fighting began.

32. Then on the I3th May 32 pilots .andaircraft were sent—say the equivalent of 2squadrons.

33. Almost immediately afterwards 8Half-Squadrons were sent. This was doneunder the impression that the loss of 8 Half-Squadrons would affect me less than that of4 entire Squadrons, because it was supposedthat H should be able to rebuild on the nucleileft behind. But this assumption was incorrectbecause I had neither the time nor the per-sonnel available for purposes of reconstruction,and the remaining half-squadrons had to beamalgamated into Composite Units with a re-sulting disorganisation and loss of efficiency.At this time, too, I was ordered to withdrawtrained pilots from squadrons and to send themoverseas as reinforcements.

34. I had now lost the equivalent of 16Squadrons, and in addition 4 Squadrons weresent to fight in France during the day and toreturn to English bases in the evening.

35. Other pilots were withdrawn from theCommand through the system by which theAir Ministry dealt direct with Groups on ques-tions of Personnel.

36. It must be remembered that during thisperiod the Home Defence Squadrons were notidle, 'but that Hurricane Squadrons were par-ticipating in the fighting to a considerable ex-tent, 4 Squadrons daily left S.E. Englandwith orders, to carry out an offensive patrol,to land and refuel in France or Belgium, andto carry out a second sortie before returningto England.

A 2

37. Hitherto I had succeeded generally inkeeping the Spitfire Squadrons out of the Con-tinental fighting. The reason for this, as statedabove, was that the supply situation was so badthat they could not 'have maintained theirexistence in face of the Aircraft Casualty Rateexperienced in France: between the 8th Mayand the i8th May 250 Hurricanes were lost.

38. When the Dunkerque fighting began,however, I could no longer maintain this policy,and the Spitfires had to take their share inthe fighting.

39. When the Dunkerque evacuation wascomplete I had only 3 Day-Fighting Squadronswhich had not been engaged in Continentalfighting, and 12 Squadrons were in the linefor the second time after having been with-drawn to rest and re-form.

40. All this time, it must be remembered,the attack on this Country had not begun;with a few accidental exceptions no bomb hadbeen dropped on our soil. \L was responsiblefor the Air Defence of Great Britain, and Isaw my resources slipping away like sand inan hour-glass. The pressure for more andmore assistance to France was relentless and).inexorable. In the latter part of May, 1940,I sought and obtained permission to appearin person before the War Cabinet and to statemy case. I was accorded a courteous andsympathetic hearing, and to my inexpressiblerelief my arguments prevailed and it was de-cided to send no more Fighter Reinforcementsto France except to cover the final evacuation.

41. I know what it must have cost theCabinet to reach this decision, but I am pro-foundly -convinced that this was one of thegreat turning points of the war.

42. Another decision, of perhaps equal im-portance, was taken at about this time. I referto the appointment of Lord Beaverbrook tothe post of Minister of Aircraft Production.The effect of this appointment can only bedescribed as magical, and thereafter the Supply.situation improved to such a degree that theheavy aircraft wastage which was later incurredduring the " Battle of Britain " ceased to bethe primary danger, its place being taken bythe difficulty of producing trained fighter pilotsin adequate numbers.

43. After the Evacuation from Dunkerquethe pressure on the Fighter Command becameless intense, but it by no means disappeared.Hard fighting took place along the coast fromCalais to Le Havre to cover the successiveevacuations from that coast. Then the centreof gravity shifted to Cherbourg and its neigh-bourhood, and the " Battle of Britain " fol-lowed on without any appreciable opportunityto rest and re-form the units which had bornethe brunt of the fighting.

44. The above considerations should be keptin mind when Appendix A (Order of Battle onthe 8th July, 1940) is "being studied.

45. The Guns and Searchlights available forthe Air Defence of Great Britain were arrangedas shown on the map which constitutes Appen-dix B.

46. The fall of Belgium and France had in-creased the danger to the South and West ofEngland, and had necessitated a considerablemodification of the original arrangements whenbombing attacks could start only .from Germansoil.


47. The distribution of Army Units was,as a matter of fact, in a condition of perpetualchange to meet new situations as they arose,and I must pay a very sincere tribute to theflexibility of the Army organisation, and to thetact, -patience and loyalty of the Commander-in-Chief of the Anti-Aircraft Command,Lt.*Gen. Sir Frederick A. Pile, Bart., K.C.B.,D.S.O., M.C., which enabled these constantchanges to be 'made without disorganisation.

48. In theory the Cx>mmander-in-Chief,Fighter Command, was the authority respon-sible for settling the dispositions of all gunsallotted to the Air Defence of Great Britain;but this was little more than a convenient fic-tion. The number of guns available was soinadequate for the defence of all the vulnerabletargets in the country, and the interests con-cerned were so diverse and powerful, that itwas not to be supposed that an individualmember of any one Service would be left toexercise such a prerogative uninterruptedly.A disproportionate amount of my time wastaken up in discussions on gun distribution,and each decision was at once greeted with afresh agitation, until finally I had to ask thatall proposals should be discussed by a smallCommittee on which all interests were repre-sented, and I normally accepted the recommen-dations of this Committee during quiet periods.During active operations I consulted GeneralPile, and we acted according to our judgment.

One rather important lesson emerged fromour experience, viz., that the general fire-con-trol of all guns in the Air Defence Systemshould be vested in the Air Defence authori-ties. I do not, of course, mean that, if an in-vasion had taken place, the guns co-operat-ing with the troops in the Field should havebeen subordinated to any A.A. Defence Com-mander, bu* the existence of " free-lance "guns*), the positions and even the existenceof which were unknown to me, was an appreci-able handicap, especially at night. It was im-possible to acquaint them with the approach 1of enemy raiders, or of the fact that our ownaircraft were working in the vicinity.

49. When the night attacks on London beganto be really serious, General Pile, in consulta-tion with myself, decided to send heavy rein-forcements. Within 24 hours the defences tothe South and South-East of London wereapproximately doubled, and the great increasein the volume of fire was immediately noticedand had a very good effect on public morale.The physical effect in the shape of .raidersdestroyed was by no means negligible, but themain effect was never generally known. Thetrack of every raid was, of course, shown onvarious operations tables, and on some nightsas many as 60 per cent, of the raidersapproaching London from the South turnedback after dropping their bombs in the opencountry or on the fringe of the Barrage.

50. The A.A. Guns at Dover enjoyedunusual opportunities for practice, with theresult that their crews became acknowledgedexperts in the art of Anti-Aircraft Gunnery.Their skill, however, was attained through thecircumstance that they and the Dover Balloon

* These guns belonged to Field Force Units. Assuch units were, of necessity, highly mobile, theirexact location was not always known to FighterCommand. Nor, after a recent move, were theyalways included in the telephone system.

Barrage were continuously the objectives ofGerman attack; they manned their guns con-tinuously night and day, and I must pay ahigh tribute to their morale, enthusiasm and"efficiency.

A report from the 6th A.A. Division, whichwas busily and typically employed, is includedat Appendices C, C.A, C.B. and C.C.

51. A short Appendix (C.D) is added show-ing the number of rounds fired per aircraftdestroyed, for the whole Anti-Aircraft Com-mand.

52. On the map which constitutes Appen-dix A.A. are shown the boundaries of Groupsand Sectors, and also the positions of the Bal-loon Barrages, together with an indication ofthe front covered by Radio Location Stationsand the area covered by the Observer Corps.

53. The Balloon Barrages had, at this stage,had little opportunity of justifying their exist-ence, except perhaps at Rosyth and ScapaFlow, since bombing attacks against landobjectives in Britain had not yet begun. Itwas thought, however, (and later experienceconfirmed this opinion), that the heavy costof their installation and maintenance, and theirdrain on man-power, were on the whole justi-fied. It is true that their material results, interms of enemy aircraft destroyed, were notimpressive, they suffered staggering casualtiesin electric storms, and had brought down anumber of our own aircraft; on the other hand,they exercise a very salutary moral effect uponthe Germans and to a great extent protectedthe vital objectives, which *hey surrounded,against low-altitude attacks and dive-bombing.

54. This is not the place to give an accountof the romantic discovery and development ofRadio Location. It may be explained, how-ever, that the backbone of the system consistedof a series of large " chain " stations at inter-vals averaging about 30 miles. These gave

> warning, by means of reflected electricalechoes, of the presence of aircraft within theradius of their effective action, which attainedto nearly 200 miles in the most favourable cir-cumstances. The average effective radius wasabout 80 miles, but they had the serious limita-tion that they failed altogether t'j give indica-tions of aircraft flying below 1,000 feet.

55. To overcome this disability, which wasparticularly hampering to operations againstlow-flying minelayers, smaller units called" C.H.L. Stations" were included in theprotective line.

56. These had a restricted range (about 30miles), and were incapable of giving heightswith any degree of accuracy; they were, how-ever, extremely accurate in azimuth, and con-stituted an essential feature of the Defensiveand Warning Systems.

57. The Radio Location system was growingso fast and had to meet so many calls fromoverseas that the training of the technical per-sonnel and the maintenance of the elaboratescientific apparatus presented great difficulties.In spite of these handicaps, however, thesystem operated effectively, and it is not toomuch to say that the warnings which it gavecould have been obtained by no other meansand constituted a vital factor in the AirDefence of Great Britain.

SUPPLEMENT TO THE LONDON GAZETTE, n SEPTEMBER, 1946 4547

58. The functions of the Observer Corps(since granted the " Royal " prefix) are toowell known to require description here.Suffice it to say that this loyal and public-spirited body of men had maintained theirwatch with admirable efficiency since the be-ginning of the war and throughout a winterof exceptional severity. It is important to notethat, at this time, they constituted the solemeans of tracking enemy raids once they hadcrossed the-coast line. Later experience wasto show that " sound plots," ^which were allthat could be given for night raiders, and air-craft flying above clouds or at extreme alti-tudes, were not adequate for purposes ofaccurate interception; but their work through-out was quite invaluable. Without it the AirRaid Warning' systems could not have beenoperated, and Inland. Interceptions wouldrarely have been made.

59. The credit for building up and develop-ing the Observer Corps in recent years is due

' largely to its Commandant, Ah CommodoreA. D. Warrington Morris; CM.G., O.B.E.

• 60. The Air Raid Warning System wasoperated centrally from Fighter CommandHeadquarters (with a small exception in theOrkneys and Shetlands).

61. The country was divided into about 130" Warning Districts," the boundaries of whichwere determined by the lay-out of the publictelephone system. These districts were shownon a map in my Operations Room, and thetracks of all enemy -raids, whether over theland or sea, were plotted by means of counters.deposited and removed as necessary by anumber of " Plotters."

62. The counters were of three colours,according to the 5-minoite period in whichthey were placed on the table: This wasnecessary to facilitate their removal at the endof 15 minutes, and so to obviate the confusioncaused by " stale plots."

' 63. Three telephone operators were in con-tinuous communication with the Trunk Ex-changes in London, Liverpool and Glasgow,and when a raid was within 20 minutes' flyingdistance of a warning district the Air RaidWarning officer would send a message, as, forinstance: " 10. Norwich. Yellow." TheLondon operator would transmit this to theLondon Trunk Exchange, and the Londonoperator would immediately retransmit it toNorwich, where other operators would pass iton to approved recipients in the Warning Dis-trict. This was a preliminary caution for theinformation of Police, Fire Stations, &c., andinvolved no public warning.

64. About 5 minutes later, if the said Dis-trict were still threatened, a " Red Warning "would be given. This was the signal for theSirens to sound. A " Green " signal indicated" Raiders Passed," and the Sirens sounded the" All Clear."

65. At night, when it became essential tomaintain exposed lights in Dockyards, Rail-way Sidings and Factories up to the lastminute, so as to obviate unnecessary loss ofworking time, a "Purple " warning was intro-duced. . This was a signal for the extinctionof exposed lights, but it did noi connote apublic warning. •' ..

66. There were also subsidiary warnings,transmitted by a fourth operator, to close downRadio Stations which might assist the enemy'snavigation by enabling him to use wirelessDirection Finding.

67. The credit for working out this systemin conjunction with the Home Office is duelargely to Air Vice-Marshal A. D. Cunningham,C.B.E.

68. The Fighter Command was dividedinto Groups and Sectors in accordance with thearrangement shown in Appendix A A. OnlyNos. n, 12 and 13 Groups were fully organisedat the beginning of the Battle. Each Groupand Sector Headquarters had an OperationsTable generally similar to that already des-cribed at Command Headquarters, butcovering an appropriately smaller area. TheBritish Isles and neighbouring seas werecovered by an imaginary " grid " which wasused by all concerned for plotting purposes.An expression consisting of one letter and fourdigits gave the position of a point with anaccuracy of i square kilometre.

69. Plots from which'tracks could be 'builtup were received first from the Radio LocationStation, and later from the Observer Corps(and to a small extent from Searchlight Detach-ments) after a raid had crossed the coast.

70. All Radio Location plots came to a" Filter Room " table at Command Head-quarters (next door to the room in which theOperations Table was situated), and, aftersurplus information had been eliminated, trackswere passed -by direct telephone line simul-taneously to my Operations Table and to thoseof Group.*, and Sectors concerned.

• 71. Observer Corps plots, on the other hand,went first to Observer Group Centres (whereplotting tables were also installed) and thenceto Sector and Fighter Group Operations tables.The tracks were then " told " to my OperationsRoom from -the Group Tables.

72. In order to avoid waste of flying effortand false Air Raid Warnings it was obviouslyvery necessary to differentiate between friendlyand enemy formations, and this was-the mostdifficult as well as the most important task ofmy Filter Room. Liaison Officers from Bomberand Coastal Commands were permanently onduty, and they were in possession of all avail-able information concerning the operations ofour own Bombers and Coastal patrols. During1940 an electrical device became generallyavailable which modified the echo received bythe Radio Location System from our own air-craft in a characteristic manner. This was ofthe greatest value.

73. The credit for working out the compli-cated details of the Filter Room 'belongs largelyto Wing Commander (now Group Captain)R. G. Hart, C.B.E.

74. It appeared to me quite impossible tocentralise Tactical control at Command Head-quarters, and even Group Commanders wouldbe too 'busy during, heavy fighting to concernthemselves, with details bf Interception.

75. The system was that the Commandshould be responsible for the identification ofapproaching formations and for the allotmentof enemy raids to Groups where any doubtexisted. Group Commanders decided whichSector should meet 'any specified raid and the


strength of the Fighter force which should beemployed. Sector Commanders detailed theFighter Units to be employed, and operated themachinery of Interception.

76. Various states of preparedness were laiddown, e.g., Released, Available (20 minutes),Readiness (5 minutes), and stand-by (2minutes), and Sectors reported all changes toGroup Headquarters, where an up-to-datepicture of the state of affairs was recorded bylights on the walls of the Operations Room.Various liaison officers from the Observer Corps,guns and searchlights were maintained inGroup and Sector Operations Rooms.

77. It will ibe seen that the Sector Com-mander had on his table the ibest availableinformation as to the position and track of anenemy formation; -but, in order to effect anaccurate interception, it was necessary that heshould also know the position and track of hisown Fighters.

78. This was recorded by means ofR/T D/F (Radio Telephony DirectionFinding). R/T signals were transmitted auto-matically for 15 seconds out of each minute byselected Fighter aircraft and were picked upby two or three D/F stations installed inSectors for the purpose. The readings werepassed1 by direct telephone lines to SectorHeadquarters, and a mechanical plotting devicegave an almost instantaneous '-plot of theFighter's position.

79. In the more recently organised Sectorsthese D/F stations had not been installed, andit was necessary to keep track of the Fightersby giving them precise orders as to speed anddirection, and plotting their tracks by DeadReckoning. This method was adequate onlyif the force and direction of the wind at variousaltitudes could be correctly estimated.

80. The Sector Commander could thus see onhis operations tables the positions and coursesof enemy formations and of his own Fighters,and was enabled so to direct the latter as tomake interceptions with the former in a goodpercentage of occasions by day. Interceptiondepended, of course, on the Fighters being ableto see the enemy, and, although the systemworked adequately against enemy formations in•daylight, the degree of accuracy obtainable was-insufficient to effect interception against nightraiders not illuminated by Searchlights, oragainst individual aircraft using cloud coverby day.

81. Orders were given to pilots in their air-craft by means of a very simple code whichcould be easily memorised. For instance" Scramble " meant Take off. " Orbit "meant Circle. " Vector 230 " meant Fly on acourse of 230 Degrees.

82. I realised that the enemy might pick upthe signals and interpret them, but any elabo-rate code was out of the question if it includedreference to some written list in the air."

83. As a matter of fact the enemy did pickup and interpret the signals in some cases, butnot much harm was done, except when theywere able to discover the height at which aformation was ordered to operate, and the timewhen it was ordered to leave its patrol lineand land.

84. " Pancake " was the signal for the latteroperation, and I therefore introduced severalsynonyms, the significance of which was notobvious to the enemy.

85. The code word for height was " Angels,"followed by the number of thousands of feet;when it appeared probable that the enemy weretaking advantage of this information I intro-duced ~a false quantity into the code signal.Thus " Angels 18 " really meant Fly at 21,000a,nd not 18,000. On more than one occasionGerman Fighter formations arriving to dive onone of our patrols were themselves attackedfrom above.

86. The system as a whole had been builtup by successive steps.over a period of aboutfour years, and I was not^flissatisfied with theway in which it stood the test of war.

87. The steps taken to devise a system ofnight Interception are described later in thisDespatch.

88. I must now give a brief account of thecharacteristics of the aircraft commonlyemployed on both sides. As regards the Fightertypes available in the Command, the bulk ofthe force consisted of Hurricanes and Spitfires;the former were beginning to be outmoded ibytheir German counterparts. They were com-paratively slow and their performance andmanoeuvrability were somewhat inadequate ataltitudes above 20,000 ft. The Spitfires wereequal or superior to anything which the Germanspossessed at the beginning of the Battle.

89. The Hurricanes and Spitfires had bullet-proof windscreens and front armour betweenthe top of the engine and the windscreen. Theyalso had rear armour directly behind the pilot,which was previously prepared and fitted assoon as we began to meet the German Fighters.The early adoption of armour gave us an initialadvantage over the Germans, but they werequick to imitate our methods. While Germanaircraft remained unarmoured, I think it isnow generally agreed that the single-seatermulti-gun fighter with fixed guns was the mostefficient type which could have been producedfor day fighting. With the advent of armoursome change in armament and/or tacticsbecame necessary,, and the subject is discussedin more detail in Appendix F.

90. The Defiant, after some striking initialsuccesses, proved to be too expensive in useagainst Fighters and was relegated to nightwork and to the attack of unescorted Bombers.

91. The Blenheim was also unsuitable forday-time combat with Fighters, owing to itslow speed and lack of manoeuvrability. It hadbeen relegated to night duties for these reasons,and because adequate space was available inits fuselage for an extra operator and thescientific apparatus which was necessary forthe development of a new night-interceptiontechnique. The cockpit had not been designedfor night flying and the night view was ex-tremely bad. Its already low performance hadbeen further reduced by certain external fittingswhich were essential for the operation of theRadio Detecting apparatus.

92. The Beaufighter was looked on as aBlenheim replacement in which most of theabove disadvantages would be overcome. Itsspeed promised to be adequate and its arma-ment consisted of 4 20-mm. Cannons instead


of the 5 .303-inch Brownings of the Blenheim.There was thus hope that decisive fire couldbe brought to bear in the short period duringwhich visual contact could be expected to bemaintained at night.

93. Like the Blenheim, it had not been de-signed as a Night Fighter (it was an adapta-tion of the Beaufort Torpedo Bomber), andthe night view from the cockpit was bad; butAir Vice-Marshal Sir Q. Brand, K.B.E.,D.S.O., M.C., D.F.C., a veteran night fighterof the previous war, had designed a".new cock-pit lay-out, which did not, unfortunately,materialise during my tenure of the FighterCommand. The output of Beaufighters wasalso very low.

94. Another-tyge.--which was pressed, into ser-vice as a Night Fighter was the Douglas D.B-7(now the Havoc). It had low fire power andcomparatively poor performance with itsoriginal engines. Its chief advantage lay inits tricycle undercarriage, which proved verypopular for landings in bad visibility. Onlyone Squadron of these was in being when I leftthe Command.

95. One Squadron of Gladiators was still inuse in the Command. As explained above, theorganisation of No. 10 Group was not com-plete, and there was no large aerodrome closeenough to Plymouth to allow of direct protec-tion being given to that town and to the Dock-yard at Devonport. A squadron of Gladiatorswas therefore located at a small aerodromecalled Roborough in the immediate vicinity.The Gladiators, though slow by modern stan-dards, were very manoeuvrable, and had givengood results in Norway by deflection shootingin the defence of fixed objectives, where theBombers could not avoid the Gladiators if theywere to reach their targets.

96. Some American single-seater aircraftwere La Great Britain, but the types then avail-able were deficient in performance and firepower and were not employed to any materialextent.

97. The Whirlwind raised high hopes in somequarters. It claimed a very high top speedand carried 4 Cannon Guns. It had, however,a totally inadequate service ceiling (about25,000 ft.) and a poor performance at thataltitude. It also suffered from a continuousseries of teething troubles, and the singleSquadron equipped with this type was never fitfor operations in my time.

98. It is very difficult to give any kind ofconcise description, of the types of Enemy Air-craft used during the Battle. The Germans,while adhering to broad standard types, werecontinually modifying and improving them byfitting more powerful engines and altering thearmament. The original Messerschmitt 109,for instance, had a performance comparablewith that of the Hurricane, but the latest typecould compete with the Spitfire, and 'had abetter ceiling. Some of them had 4 machineguns arid others had 2 machine guns and 2cannons. Some of them were fitted to. carrybombs and some were not.

99. The Messerschmitt no was a twin-engined fighter designed primarily for escortingBombers arid used also as a Fighter-Bomber.It was somewhat faster than the Hurricane, butnaturally much lesfe manoeuvrable than the

single-engined types. Its usual armament was2 fixed cannons and 4 machine guns firing for-ward, and one free machine gun firing to therear. Our pilots regarded it as a less formid-able opponent than the later types of M.E. 109.

100. The Heinkel 113 Fighter made itsappearance in limited numbers during theBattle. It was a single seater, generally re-sembling the M.E. 109. Its main attributeswere high performance and ceiling, so that itwas generally used in the highest of the severallayers in which attacking formations wereusually built up.

101. The Junkers.87 was a single-enginedDive-Bomber. It had a low performance (topspeed well under 250 m.p.h.). It'had 2 fixedmachine guns firing forward and one free gunfiring to the rear. When it was able to operateundisturbed by Fighters it was the Germans'most efficient Bomber against land or sea tar-gets owing to the great accuracy with whichit dropped its bombs; but when it was caughtby fighters it was nothing short of a death-trap, and formations, of J.U. 87's were prac-tically annihilated on several occasions.

102. The Heinkel in and the various typesof Dornier (17, I7Z and 215) constituted themain element of the German striking force.They were twin-engined aircraft and weregenerally similar, although the former wasslightly the larger. Their speed was somethingover 250 m.p.h., and then* armament con-sisted normally (-but not always) of 4 freemachine guns firing backwards and one firingforwards. Their radius of action varied withtankage and bomb load, but, if necessary, allobjectives in England and Northern Irelandcould be reached from aerodromes in France.

103. The Junkers 88 was the most modernof the German (Bombers. It also was a twin-eng^ned type with a performance of about290 m.p.h. Its armament was generallysimilar to that of the H.E. in and the Dormersand it had a slightly longer range. It couldbe used on occasions as a Dive-Bomber and,though probably somewhat less .accurate thanthe J.U. 87, was much less vulnerable owingto its superior performance and armament.

1104. Before beginning an account of theBattle, I must refer briefly to the publicationentitled The Battle of Britain, issued by theAir Ministry. This, if I may say so, is anadmirable account of the Battle for public con-sumption, and I am indebted to it, as well asto the book Fighter Command, by Wing Com-mander A. B: Austin, for help hi the compila-tion of this Despatch. There is very littlewhich I should have wished to alter, even ifcircumstances had permitted my seeing it be-fore publication (I was absent in America atthe time), but there are two points to whichI should like to draw attention:—

105. In the diagram on page 7 the speedof the. Hurricane is seriously over-rated at 335ni.p.h. I carried out a series of trials toobtain the absolute and comparative speedsof Hurricanes and Spitfires at optimum heights.Naturally the speeds of individual aircraftvaried slightly, but the average speed of sixHurricanes came out at about 305 m.p.h.

106. The second' point is of greater import-ance. I quote from page 33: " What theLuftwaffe failed to .do was to destroy theFighter Squadrons of the Royal Air • Force,


which were, indeed, stronger at the ~end of thebattle"than at the beginning." (The italicsare mine.)

107. This statement, even if intended onlyfor popular con-sumption, tends to lead to anattitude of complacency which may be verydangerous in the future. Whatever the studyof paper returns may have shown, the factis that the situation was critical in the extreme.Pilots had to be withdrawn from the Bomberand Coastal Commands and from the FleetAir Arm and flung into the Battle after hastypreparation. The majority of the squadronshad been reduced to the sjatus of training units,and were fit only for operations against un-escorted bombers. . The remainder werebattling daily against heavy odds.

108. The indomitable courage of the FighterPilots and the skill of their Leaders brought usthrough the crises, and the morale of theGermans eventually cracked because of thestupendous losses which they sustained.

109. Any attempt to describe the events ofthe Battle day by day would make this Des-patch unduly long and wouHd prevent thereader from obtaining a comprehensive pictureof the events. I have therefore decided toshow the main features of each day's fightingin an Appendix on which our own and theGermans' aircraft casualties will be showngraphically. I shall then be able to deal withthe progress of the Battle by phases, thusavoiding the tedious and confusing method ofday-to-day description. The information isgiven in Appendix D.

no. As regards our casualties, we generallyissued statements to the effect that we lost " x"aircraft from Which " y " pilots were saved.This did not of course mean that " y " pilotswere ready immediately to continue the Battle.Many of them were suffering from wounds,burns or other injuries which precluded theirreturn to active flying temporarily or per-manently.

in. It might also be assumed that all Ger-man crews who were in aircraft brought downduring the Battle, were permanently lost to theLuftwaffe. because the fighting took place onour side of the Channel. Such an assumptionwould not be literally true, because the Ger-mans succeeded in rescuing a proportion of theircrews from the sea by means of rescue boats,floats and aircraft which will be later described.

112. The decisive features of the Battle werethe Ratio of Casualties incurred by ourselvesand the Germans, and the Ratio of Casualtiesto the numbers actively employed on both sides.Appendix D has been drawn up with thesepoints in mind.

113. I must disclaim any exact accuracy inthe estimates of Enemy losses. All that I cansay is that the utmost care was taken to arriveat the closest possible approximation. Special-intelligence officers examined pilots individuallyafter their combats, and the figures claimed areonly those recorded as " Certain." If we allowfor a percentage of over-statement, and the factthat two or more Fighters were sometimes firingat the same enemy aircraft without being awareof the fact, this can fairly be balanced by thecertainty that a proportion of aircraft reportedas " Probably Destroyed " or " Damaged "failed to return to their bases. The figures, then,

are put forward as an honest approximation.Judging by results, they are perhaps not farout.

114. The German claims were, of course,ludicrous; they may have been deceived aboutour casualties, but they know they were lyingabout their own.

115. I remember being cross-examined inAugust by the Secretary of State for Air aboutthe discrepancy. He was anxious about theeffect on the American people of the widedivergence between the claims of the two sides.I replied that the Americans would soon findout the truth; if the Germans' figures wereaccurate they would be in London in a week,otherwise they would not.

116. Our estimate of German casualties, then,may be taken as reasonably accurate for prac-tical purposes; but our estimates of the strengthin which attacks were made is based on muchless reliable evidence. The Radio-Locationsystem could give only a very approximate esti-mate of numbers and was sometimes in errorby three or four hundred per cent. This is noreflection on the System, which was not de-signed or intended to be accurate in the estima-tion of considerable numbers; moreover, severalstations were suffering from the effects of severebombing attacks. As the average height ofoperations increased, the Observer Corps be-came Jess and less able to make accurate esti-mates of numbers, and, in fact, formations wereoften quite invisible from the ground.

117. Even the numerical estimates made bypilots who encountered large formations in theair are likely to be guesswork in many instances.Opportunities for deliberate counting of enemyaircraft were the exception rather than the rule.

118. Although Secret Intelligence sourcessupplemented the information available, it ispossible that on days of heavy fighting com-plete formations may have escaped recordedobservation altogether.

119. This is unfortunate, because it isobviously of the greatest importance to deter-mine the relative strengths of the Attack andthe Defence, and to know the ratio of losses toaircraft employed which may be expected tobring an attack to a standstill in a given time.History will doubtless elucidate the uncer-tainty, but perhaps not in tune for the informa- •tion to be of use in the present war.

120. My personal opinion is that, on days ofslight activity, our estimates are reasonablyaccurate, but that they probably err on the lowside on days of heavy fighting when many andlarge formations were employed.

121. As has been explained above, fewsquadrons were fresh and intact when the Battlebegan. No sufficient respite has been grantedsince the conclusion of the Dunkerque fightingto rest the Squadrons which had not left theFighter Command, and to rebuild those whichhad undergone the ordeal of fighting from aero-dromes in Northern France. These last hadbeen driven from aerodrome to aerodrome, ableonly to aim at self-preservation from almostcontinuous attack by Bombers and Fighters;they were desperately weary and had lost thegreater part of their equipment, since aircraftwhich were unserviceable only from slightdefects had to be abandoned.


PART II.—THE BATTLE.122. The Battle may be said to have divided

itself broadly into 4 Phases: First, the attackon convoys and Coastal objectives, such asPorts, Coastal Aerodromes and Radio LocationStations. Second, the attack of Inland FighterAerodromes. Third, the attack on London.And fourth, the Fighter-Bomber stage, wherethe target was of importance quite subsidiaryto the main object of drawing our Fighters intothe air and engaging them in circumstances asdisadvantageous to us as possible. Thesephases indicated only general tendencies; theyoverlapped and were not mutually exclusive.

123. It has been estimated that the Germanssent over, on an average throughout the Battle,four Fighters to_each Bomber or Fighter-Bomber, but any such estimate must be veryrough.

124. I must emphasise, throughout, theextreme versatility of the German methods bothin the timing and direction of their attacks, andin the tactical formations and methodsemployed.

125. They enjoyed the great advantage ofhaving a wide front from which attacks couldbe delivered. First a blow would be deliveredfrom Calais, perhaps against London; then aftera carefully-timed interval, when n GroupFighters might be expected to, be at the end oftheir petrol endurance, a heavy attack wouldbe made on Southampton and Portland. Otherattacks, after being built up to formidabledimensions, would prove to be only feints, andthe Bombers would turn away before reachingcoast of England, only to return again in halfan hour, when the Fighters, sent up to interceptthem, were landing.

126. Time-honoured methods of escort wereat first employed. A strong Fighter formationwould fly a mile or so behind and above theBombers. When the Germans found that ourFighters could deliver a well-timed attack on theBombers before the Fighters could intervene,or when our Fighters attacked from ahead orbelow, each move was met by a counter-moveon the part of the Germans, so that, in Septem-ber, Fighter escorts were flying inside theBomber formation, others were below, and aseries of Fighters stretched upwards to 30,000feet or more.

127. One Squadron Leader described his im-pressions of the appearance of one of theseraids; he said it was like looking up the escala-tor at Piccadilly Circus.

128. I must pay a very sincere tribute to theAir Officer Commanding No. n Group, AirVice-Marshal K. R. Park, C.B., M.C., D.F.C.,for the way in which he adjusted his tactics andinterception methods to meet each new develop-ment as it occurred.

129. Tactical control was, as has alreadybeen stated, devolved to the Groups; buttactical methods were normally laid down byCommand Headquarters. During periods ofintense fighting, however, there was no time forconsultation, and Air Vice-Marshal Park actedfrom day to day on his own initiative. Wediscussed matters as opportunity offered.

130. He has reported on the tactical aspectsof the Battle in two very interesting documents,which are, however, too long to reproducehere.

131. A close liaison was kept between Nos.10 and ii and 12 Groups. It sometimes hap-pened that, in the heaviest attacks, practically.all ii Group Fighters would be in the air.11 Group would then ask 12 'Group to send aformation from Duxford to patrol over theaerodromes immediately East of London so thatthese might not be attacked when defenceless.

132. Mutual -help was also arranged betweenNos. 10 and H Groups. When Portsmouthwas attacked, for instance, No. 10 would helpNo. ii Group, and vice versa when the attackwas on Portland or some Convoy to the Westof the Isle of Wight.

133. The amount of physical damage doneto Convoys during the first phase was not ex-cessive. About five ships (I think) wereactually 'sunk by bombing, others weredamaged, and Convoys were scattered onoccasion. It was, of course, much easier toprotect the Convoys if-they kept as close aspossible to-the English Coast, but one Convoyat least was routed so as to pass close toCherbourg, and suffered accordingly. Later,it was arranged that Convoys should traversethe most dangerous and exposed stretches bynight, and Convoys steaming in daylight either-had direct protection by Fighter escorts, or elsehad escorts at " Readiness " prepared to leavethe ground directly danger threatened.

,134. Three of ,the Radio Location Stationsin the South of England suffered rather severedamage and casualties. No Station was per-manently put out of action, , and the worstdamage was repaired in about a month, thoughthe Station was working at reduced efficiencyin about half that time. The operating per-sonnel, and particularly the women, behavedwith great courage under threat of attack andactual bombardment.

135. As regards aerodromes, Manston wasthe worst sufferer at this stage. It, Hawkingeand Lympne were the three advanced groundson which we relied for filling up tanks whena maximum range was required for operationsover France. They were so heavily attackedwith bombs and machine guns that they weretemporarily abandoned. This is not to saythat they could not have been used if theneed had been urgent, but, for interceptionat or about our own coastline, aerodromes andsatellites farther inland were quite effective.

136. Heavy damage was done to buildings,but these were mostly non-essential, 'becauseaircraft were kept dispersed in the open, andthe number of men and women employed wasnot large in comparison with the number ata Station which was the Headquarters of aSector.

137. Works personnel, permanent and tem-porary, and detachments of Royal Engineerswere employed in filling up the craterg on theaero'dromes. Experience at this stage showedthat neither the personnel nor the material pro-vided were adequate to effect repairs with thenecessary speed, and the strength and mobilityof the repair parties was increased. Stocksof " hard-core " rubble had been collected atFighter aerodromes before the war.

138. It may be convenient here to continuethe subject of damage to Fighter Stations otherthan those attacked in the first Phase.

139. Casualties to personnel were slight, ex-cept in cases where a direct hit was made on


a shelter trench. The trenches commonly inuse were lined with concrete and were roofedand covered with earth; but they gave no pro-tection against a direct hit, and, in the natureof things, they had to-be within a short distanceof the hangars and offices.

140. Only non-essential personnel took coyer;aircraft crews and the staff of the OperationsRoom remained at their posts. The moraleof the men and women of ground crews andstaffs was high and remained so throughout.

141. At Kenley and at Biggin Hill directhits were sustained on shelter trenches, at thelatter place by a bomb of 500 kilog. or more.The trench and its 40 occupants wereannihilated.

•142. Wooden hangars were generally set onfire by a bombing attack, and everything inthem destroyed.

143. Steel, briok and concrete hangars, onthe other hand, stood up well against attack,though, of course, acres of glass were broken.Hangars were generally empty or nearly so,and those aircraft which were destroyed inhangars were generally under repair or majorinspection which made it necessary to workunder cover.

144. It must, nevertheless, be definitely re-corded that the damage done to Fighter aero-dromes, and to their communications andground organisation, was serious, and has beengenerally under-estimated. Luckily, theGermans did not realise the success of theirefforts, and shifted their objectives before thecumulative effect of the damage had becomeapparent to them.

145. Damage to aerodrome surface was nota major difficulty. It was possible for theGermans to put one or two aerodromes likeMansion and Hawkinge out of action for atime, but we had so many satellite aerodromesand landing grounds available that it was quiteimpossible for the Germans to damage seriouslya number of aerodromes sufficient to causemore than temporary inconvenience.

146. This is an important point, because, inmobile warfare, Fighter aerodromes cannot behastily improvised in broken country, and thenumber of aerodromes actually or potentiallyavailable is a primary factor in the " Appre-ciation of a Situation."

147. Sector Operations Rooms were protectedby high earth embankments, so that they wereimmune from everything except a direct hit,and, as a matter of fact, no direct hit by aheavy bomb was obtained on any OperationsRoom. Communications were, however, con-siderably interrupted, and I must here pay atribute to the foresight of Air Vice-MarshalE. L. Gossage, C.B., C.V.O., D.S.O., M.C.,who commanded No. n Group during the firsteight months of the war. At his suggestion" Stand-by" Operations Rooms were con-structed at a distance of two or three miles fromSector Headquarters, and a move was madeto these when serious attacks on Fighter Aero-dromes began. They were somewhat incon-venient make-shifts, and some loss of efficiencyin Interception resulted from their -use. Workwas put in hand immediately on more perman-ent and fully-equipped Operations Rooms con-veniently remote from Sector Headquarters;these though in no way bomb-proof, were

outside the radius of anything aimed at theSector Aerodrome, and owed then* immunity toinconspiouousness. Most of these were finishedby October 1940.

148. Aerodrome Defence against parachutetroops, or threat of more serious ground attack,was an important and a difficult problem, be-cause Home Defence troops w'ere few and wereneeded on the Beaches, and the majority oftroops rescued from Dunkerque were dis-organised and unarmed. The Commander-in-Chief, Home Forces, did, however, make troopsavailable in small numbers for the more im-portant aerodromes and armoured vehicles wereextemporised. The difficulty was enhanced bya comparatively recent decision of the AirMinistry to disarm the rank ajjd file of the RoyalAir Force. The decision was reversed, 'but itwas some time before rifles could be providedand men trained in their use.

149. The slender resources of the Anti-Air-craft Command were strained to provide gunsfor the defence of the most important Fighterand Bomber Aerodromes. High Altitude andBofors guns were provided up to the limit con-sidered practicable, and the effort was rein-forced by the use of Royal Air Force detach-ments with 'Lewis guns and some hundreds of2O-mm. Cannon which were not immediatelyrequired for use in Aircraft

150. A type of small Rocket was also in-stalled at many aerodromes. These werearranged in lines along the perimeter, andcould be fired up to a height of something under1,000 feet in the face of low-flying attack. Theycarried a small bomb on the end of a wire.Some limited success was claimed during a low-flying attack at Kenley, and they probably hadsome moral effect when their existence becameknown to the Enemy. They were, of course,capable of physical effect only against very lowhorizontal attacks.

151. The main safeguard for Aircraft againstair attack was Dispersal. Some experimentson Salisbury Plain in the Summer of 1938 hadshown that dispersal alone, without any formof splinter-proof protection, afforded a reason-able safeguard against the forms of attack prac-tised by our own Bomber Command at thetime. Thirty unserviceable 'Fighters were dis-posed in a rough ring of about 1,000 yardsdiameter, and the Bomber Command attackedthem for the inside of a week with every missilebetween a 500-pound bomlb and an incendiarybullet, and without any kind of opposition. Theresult was substantially:—3 destroyed, idamaged beyond repair, n seriously damagedbut repairable, and the rest slightly damaged oruntouched.

152. I therefore asked that small splinter-proof pens for single aircraft should be providedat all Fighter Aerodromes. This was notapproved, but I was offered pens for groups ofthree. I had to agree to this, because it waslinked up with the provision of, all-weatherrunways which I had been insistently de-manding for two years, and it was impera-tively necessary that .work on the runwaysshould not be held up by further discussionabout pens. I think that the 3-aircraft penswere too big. They had a large open face tothe front and a concrete area, of the size of twotennis courts, which made an ideal surface forthe bursting of direct-action bombs. Eventually,splinter-proof partitions were made inside., the

SUPPLEMENT TO THE LONDON GAZETTE, u SEPTEMBER, 1946 4553

pens, and till then some aircraft were parkedin the open. Losses at dispersal points werenot serious; the worst in my recollection was 5aircraft destroyed or seriously damaged in oneattack. Small portable tents were providedwhich could be erected over the centre portionof an aeroplane, leaving the tail and wing-tipsexposed. These protected the most importantparts and enabled ground crews to work in badweather.

153. About this time an improvised RepairSystem was organised and worked*well. Withthe hearty co-operation of the Ministry ofAircraft Production it was decided that Unitsshould be relieved of all extensive repairs andoverhauls, both because of their preoccupationin the Battle s(iid because of the danger offurther damage b'eing done by enemy actionto aircraft under repair. Broadly speaking,any aircraft capable of returning to its basewas capable of another 15 minutes' straightflight to a Repair Depot: aircraft incapable offlight were sent by road. Small repairs, suchas the patching of bullet holes, were done bythe Unit. Two such Repair Depots were im-provised about 30 miles to the west of London,and this undoubtedly prevented an accumula-tion of unserviceable aircraft at Fighter Stations.

154. It was also about this time that thefinal decision was made to relegate the Defiantto night operations. It had two serious dis-abilities; firstly, the brain flying the aeroplanewas not the brain firing the guns: the gunscould not fire within 16 Degrees of the line offlight of the aeroplane and the gunner was dis-tracted from his task by having to direct thepilot through the Communication Set. Secondly,the guns could not be fired below the horizontal,and it was therefore necessary to keep belowthe enemy. When beset by superior numbersof Fighters the best course to pursue was toform a descending spiral, so that one or moreDefiants should always be in a position to bringeffective fire to bear. Such tactics were, how-ever, essentially defensive, and the formationsometimes got broken up before they could beadopted. In practice, the Defiants suffered suchheavy losses that it was necessary to relegatethem to night fighting, or to the attack of un-escorted Bombers.

155. The above remarks have carried me be-yond the first phase of the Battle and into thesecond; but I find it impossible to adhere toa description of the fighting phase by phase.The Enemy's Strategical, as well as hisTactical moves had to be met from day to dayas they occurred, and I give an account of myproblems and the lessons to be derived fromthem roughly in the order of their incidence.The detailed sequence of events is sufficientlyindicated in the Diagram at Appendix " D."

156. Throughout the Battle, of course, fight-ing continually occurred over the sea, and Ger-man aircraft, damaged over England, had toreturn across the Straits of Dover or the EnglishChannel. Far more German than British crewsfell into the sea. The Germans therefore de-veloped an elaborate system of sea-rescue.Their Bombers had inflatable rubber dinghies,and various other rescue devices were adopted.Crews were provided with bags of a chemicalknown as fluorescine, a small quantity of whichstained a large area of water a vivid green.Floating refuges with provisions and wirelesssets were anchored off the French coast. " E

Boats " and rescue launches were extensivelyemployed, and white-painted float-planes,marked with the Red Cross, were used even inthe midst of battle. We had to make itknown to the Germans that we could notcountenance the use of the Red Cross in thismanner. They were engaged in rescuing com-batants and taking them back to fight again, andthey were also in a position, if grantedimmunity, to make valuable reconnaisance re-ports. In spite of this, surviving crews of theseaircraft appeared to be surprised and aggrievedat being shot down.

157. Our own arrangements were lesselaborate. Life-saving jackets were painted aconspicuous yellow, and later the fluorescinedevice was copied. Patrol aircraft (not underthe Red Cross) looked out for immersed crews,and a chain of rescue launches with specialcommunications was installed round the coast.Our own shipping, too, was often on the spot,and many pilots were rescued by Naval orMerchant vessels.

158. This is perhaps a convenient oppor-tunity to say a word about the ethics of shoot-ing at aircraft crews who have " baled out "in parachutes.

159. Germans descending .over 'England areprospective Prisoners of War, and, as such,should be immune. On the other hand, Britishpilots descending over England are still poten-tial Combatants.

160. Much indignation was caused by thefact that German pilots sometimes fired on ourdescending airmen (although, in my opinion,they were perfectly entitled to do so), butI am glad to say that in many cases they re-frained and sometimes' greeted a helplessadversary with a cheerful wave of the hand.

161. Many of the targets attacked during thefirst two phases of the iBattle were of littlemilitary importance, and had but slight effecton our War Effort. Exceptions to this wereday-attacks carried out on the Spitfire works^atSouthampton and the sheds at Brooklaridswhere some of our Hurricanes were assembledand tested. Both these attacks had some effecton output, which would have been serious butfor the anticipatory measures taken by LdirdBeaverbrook.

•162. About this time one Canadian, twoPolish and one Czech squadrons became fit forOperations.

163. A squadron of Canadian pilots of theRoyal Air Force (No. 242) had been in exist-ence for some months, and was one of thesquadrons which went to France in June tocover the evacuation from the West Coast. Onits return it became one of the foremost fightingSquadrons in the Command, under the leader-ship of the very gallant Squadron Leader (nowWing Commander) D. R. S. Bader, D.S.O.,D.F.C., No. i (Canadian) Squadron, nowalso came into the line and acquitted itself withgreat distinction.

164. I must confess that I had been a liffledoubtful of the effect which their experience intheir -own countries and in France might havehad upon the Polish and Czech pilots, but mydoubts were soon laid to rest, because all threeSquadrons swung in the fight with a dash andenthusiasm which is beyond praise. Theywere inspired by a burning hatred for the


Germans which made them very deadly oppon-ents. The first Polish Squadron. (No. 303)in No. ii Group, during the course of a month,shot down more Germans than any British unitin the same period. Other 'Poles and Czechswere used in small numbers in BritishSquadrons, and fought very gallantly, but thelanguage was a difficulty, and they were prob-ably most efficiently employed in their ownNational units. Other foreign pilots were em-ployed in British Squadrons, but not in appre-ciable numbers. The American " Eagle "Squadron was in process of formation duringthe Battle.

165. The Auxiliary Squadrons were by thistime practically indistinguishable fromRegulars. It will be remembered that theScottish Auxiliaries were responsible for thefirst Air success of the War in the Firth ofForth. To set off against the discontinuity oftheir training in peace time they had the greatadvantage of permanency of personnel, andthe Flight Commanders at the outbreak of theWar were senior and experienced. At the sametime, this very permanence led to the averageage of the pilots being rather high for intensivefighting, which exercises a strain which theaverage man of 30 cannot support indefinitely.This point has now ceased to be of importancebecause of fresh postings. It is mentionedonly because it is a factor to be kept in mindin peace time. -No praise can be too high forthe Auxiliaries, both as regards their keennessand efficiency in peace time and their fightingrecord in war.

166. I may perhaps mention the question ofthe Long Range Guns which were mountedalong the coast of France near Cap Grisnez.They were within range of our coastal aero-dromes, which they occasionally i subjected toa desultory shelling. Their main targets, how-ever, were Dover and the Convoys passingthrough the Straits. So far as I am aware,neither they nor the guns which we installedas, counter measures, had any great influenceon the air fighting, but they did of coursemake it impossible for any of our warshipsto approach the French coast in clear weather,and might have had an important effect if ithad been possible for the Germans to launchan invading army.

167. About the end of the second phase, theproblems of keeping units up to strength and ofrelieving them when exhausted began to assumeformidable proportions. It was no new experi-ence, because the drain of units and pilots toFrance, coupled with the Dunkerque fighting,had created similar problems in the Spring.

168. The comparative relaxation in the inten-sity of the fighting in June and July hadafforded a little respite, but units had only par-tially recovered and were neither fresh nor up tostrength when the fighting again becameintense.

169. When Squadrons became exhausted,obviously the most satisfactory way of rein-foftement was by means of moving completeunits, and this was done when time allowed.Serviceable aircraft were transferred by air,and Operational Aircraft Crews (about 35 menper Squadron) were transferred by Civil Air-craft put at my disposal for the moves. Theremainder of the personnel travelled by trainor motor transport according to circumstances.

Some of the distances involved were consider-able, as for instance when a Squadron fromWick had to be brought down in the LondonArea.

170. The First-line strength of a Squadronwas 16 aircraft, of which not more than 12were intended to be operationally availableat any one time. The other 4 would normallybe undergoing Inspection or Overhaul. Inaddition to this there was a small reserve-ofthree to five -aircraft per Squadron availableon the station.

171. There was a limit to the number oftrained pilots which could be kept on thestrength of a Squadron even in times of opera-tional passivity, because not more than about25 could be kept in full practice in FlyingDuties.

172. A fresh squadron coming into an activeSector would generally bring with them 16aircraft and about 20 trained pilots. Theywould normally fight until they were no longercapable of putting more than 9 aircraft intothe air, and then they had to be relieved. Thisprocess occupied different periods according tothe luck and skill of the unit. The normalperiod was a month to six weeks, but someunits had to be replaced after a week or 10days.

173. Air Vice Marshal Park found that theheaviest casualties were often incurred bynewly-arrived Squadrons owing to their non-famih'arity with the latest developments of airfighting.

174. It soon became impossible to main-tain the to-and-fro progress of complete unitpersonnel from end to end of the country, andthe first limitation to efficiency which had to beaccepted was the retention of the majority ofpersonnel at' Sector Stations and the transferonly of flying personnel and aircraft crews.This limitation was regrettable because itmeant that officers and men were strange toone another, but worse was to come.

175. By the beginning of September theincidence of casualties became so serious that afresh squadron would become depleted and ex-hausted before any of the resting and reform-ing squadrons was ready to take its place.Fighter pilots were no longer being producedin numbers sufficient to fill the gaps in thefighting ranks. Transfers were made from theFleet Air Arm and from the Bomber andCoastal Commands, but these pilots naturallyrequired a short flying course on Hurricanesor Spitfires and some instruction in FormationFlying, Fighter Tactics and Interceptionprocedure.

176. I considered, but discarded, theadvisability of combining pairs of weak unitsinto single Squadrons at full strength, forseveral reasons, one of which was the difficultyof recovery when a lull should come. Anotherwas that ground personnel would be wasted,and a third was that the rate at which thestrength of the Command was decreasingwould be obvious.

177. 1 decided to form 3 Categories ofSquadron: —

(a) The units of n Group and on itsimmediate flanks, which were bearing thebrunt of the fighting.


(6) A few outside units to be maintainedat operational strength and to be availableas Unit Reliefs in cases where this was un-avoidable.

(c) The remaining Squadron? of the Com-mand, which would be stripped of theiroperational pilots, for; the benefit of the ASquadrons, down to a level of 5 or 6. TheseC Squadrons could devote their main ener-gies to the training of new pilots, and,although they would not be fit to meet Ger-man Fighters, they would be quite capableof defending their Sectors against unescortedBombers, which would be all that they wouldbe likely to encounter.178. The necessity for resorting to such

measures as this indicates the strain which hadbeen put on the Fighter Command and thePilot Training organisations by the casualtieswhich the Command had suffered in thisdecisive o Battle.

179. In the early stages of the fight Mr.Winston Churchill spoke with affectionate rail-lery of me and my " Chicks. " He couldhave said nothing to make me more proud;every Chick was needed before the end.

180. I trust that I may be permitted torecord my appreciation of the help given me bythe support and confidence of the Prime Minis-ter at a difficult and critical time.

181. In the early days of the War the ques-tion of the provision .of Operational TrainingUnits (or Group Pools, as they were called atthat time) was under discussion. It was re-ferred to in the correspondence which I havementioned in paragraph 17 of this Despatch.At that time I was so gravely in need of addi-tional Fighter Squadrons that I was willing todo without Group Pools altogether while wewere still at long range from the GermanFighters.

182. The functions of these Group Pools, orO.T.Us., was to accept pilots direct from Fly-ing Training Schools or non-fighter units ofthe Royal Air Force and train them in thehandling of Fighter types, formation flying,fighting tactics, and R/T control and intercep-tion methods. I realised that the Fightersin Francs could not undertake this work andmust have a Group Pool allotted primarily tomeet their requirements, but I felt that, so longas we at Home were out of touch with Ger-man Fighters, I would prefer to put all avail-able resources into new Squadrons and toundertake in Service Squadrons the finaltraining of pilots coming from Flying TrainingSchools, provided that they had done some for-mation flying and night flying, and had fired-their guns in the air.

183. Of course, when intensive fightingbegan, final training of pilots in Squadronscould no longer be given efficiently, and at thetime of the Battle three O.T.Us, were in exist-tence. It was found that three weeks wasabout the mimimum period which was of prac-iical value, but that a longer course, up to sixweeks, was desirable when circumstancespermitted.

184. During the Battle the output from theO.T.Us. was quite inadequate to meet thecasualty rate, and it was not even possibleio supply from the Flying Training Schools thenecessary intake to the O.T.Us.

185. The lack of flexibility of the Trainingsystem, therefore, proved to be the " bottle-neck " and was the cause of the progressivelydeteriorating situation of the Fighter Com-mand up till the end of September. This state-ment is in no sense a criticism of the FlyingTraining Command; The problem, as I stateit here, can have no ideal solution and somecompromise must be adopted.' 186. Assuming that in periods of maximumquiescence the Fighter Squadrons of the RoyalAir Force require an intake of x pilots perweek, in periods of intense activity they requireabout ten times the number.

187. It is necessary to start the flying train-ing of a pilot about a year before he is readyto engage Enemy Fighters, and therefore thetraining authorities should be warned, a yearahead, of the incidence of active periods. Thisis obviously impossible. If they try to be readyfor all eventualities by catering for a con-tinuous output to meet a high casualty rate/the result is that, during quiet periods, pilotsare turned out at such a rate that they cannotbe absorbed, or even given enough flying toprevent their forgetting what they have beentaught. If, on the other hand, they cater forthe normal wastage rate, Fighter Squadrons arestarved of reinforcements when they are mostvitally needed.

188. The fundamental principle which mustbe realised is that Fighter needs, -when they,arise, are not comparative with those of otherCommands, btit absolute. An adequate andefficient Fighter force ensures the Security ofthe Base, without which continuous operationsare impossible.

189. -If the Fighter defence had failed in theAutumn of 1940, England would have -been in-vaded. The paralysis of their fighters in theSpring was an important factor in the collapseof the French resistance. Later, the unavoid-able withdrawal of the Fighters from Creterendered continued resistance impossible.

190. Day Bomber and Army Co-operationaircraft can operate when their. own Fightersare predominant, but are driven out of the skj£when the Enemy Fighters have a free hand.

191. I submit some suggestions by whichthe apparently insuperable difficulties of theproblem may be reduced.

(a) Start by aiming at a Fighter outputwell above that needed in quiescent periods.

(&) Ensure that at Flying TrainingSchools, pupils earmarked for other dutiesmay be rapidly switched over \ to Fightertraining.

(c) Organise the O.T.Us. with a" Normal " and an " Emergency "Syllabus, the latter lasting for three weeksand the former twice as long.

(d) Fill up the Service Fighter Squadronsto a strength of 25 pilots, or whatever theC.-in-C. considers to be the maximum whichcan be kept in flying and operational' prac-tice.

(e) Form Reservoirs, either at O.T.Us, orin special units where surplus pilots maymaintain the flying and operational standardwhich they have reached.

(/) When the initiative lies in our hands(as, for instance, when we are planning todeliver an offensive some time ahead), the


intake of Flying Training Schools should beadjusted to cater for the additional stresswhich can be foreseen.

(g) (And this applies principally to over-seas theatres of war where rapid reinforce-ment is impossible.) 'Let the Day Bomberand Army Co-operation Squadrons have anumber of Fighters on which they can flyand train as opportunity offers. This is arevolutionary suggestion, but it is made inall seriousness. If then- Fighters are over-whelmed the Day Bomber and Army Co-operation units will not be able to operateat all. No very high standard of trainingshould (be attempted, especially in Radio-controlled Interception methods: but the in-tervention of these units as Fighters, workingin pairs or small formations, might well proveto be the decisive factor in a critical situa-tion.192. It will be observed that, at the end of

the second Phase of the iBattle, the power ofreinforcing by complete units had substantiallydisappeared. We still possessed an effectivereserve of trained pilots, but they could be madeavailable only by stripping the Squadronswhich were not engaged in the South and South-East of England.

193. The effective strength of the Commandwas running down, -though the fact was notknown to the public, nor, I hoped, to theGermans. They for then: part must certainlybe feeling the effect of their heavy losses, butthere was very little indication of any loss ofmorale, so far as could be seen from a dailyscrutiny of the examinations of Prisoners ofWar. Our own pilots were fighting with un-abated gallantry and determination.

194. The confidence of the German HighCommand probably received something of ashock about this time. The sustained resist-ance which they were meeting in South-EastEngland probably led them to believe thatFighter Squadrons bad been withdrawn, whollycff in part, from the North in order to meetthe attack. On the I5th August, therefore,two large raids were sent, one to Yorkshireand one to Newcastle. They were escortedby Fighters. The distance was too great forMe. '1093, but not for Me. nos.

195. H the assumption was that our Fightershad been withdrawn from the North, the con-trary was soon apparent, and the bombers re-ceived such a drubbing that the experiment wasnot repeated. I think that this incident prob-ably had a very depressing influence on theoutlook of the German High Command.

196. As I have said, our own pilots werefighting with the utmost -gallantry and deter-mination, but the mass raids on London, whichwere the main feature of the third phase ofthe Battle, involved a tremendous strain onunits which could no longer be relieved as such.Some Squadrons were flying 50 and 60 hoursper diem.

•197. Many of the pilots were getting verytired. An order was in existence that all pilotsshould have 24 hours' leave every week, duringwhich they should be encouraged to leave theirstation and get some exercise and change ofatmosphere: this was issued as an order so thatthe pilots should be compelled to avail them-selves of the opportunity to get the necessaryrest and relaxation. I think it was generally

obeyed, but I fear that the instinct of dutysometimes over-rode the sense of discipline.Other measures were also taken to providerest and relaxation at Stations, and sometimesto find billets for pilots where they could sleepaway from their Aerodromes.

198. During this third phase the problemarose, in an acute (form, of the strength ofFighter formations which we should employ.When time was the essence of the problem, twosquadrons were generally used by A.V.-M. Parkin No. ii Group. He had the responsibilityof meeting attacks as far to the Eastward aspossible, and the building <up of a four-squadronformation involved the use of a rendezvousfor aircraft from two or more aerodromes. Thisled to delay and lack of flexibility in leader-ship.

199. On the other hand, when No. 12 Groupwas asked to send down protective formationsto guard the aerodromes on the Eastern fringeof London, it was often possible to build up bigformations, and these had great success onsome occasions, though by no means always.

200. Because a similar situation may wellarise in future, I think that it is desirable toenter into some detail in this connection.

201. I may preface my remarks by statingthat I am personally in favour of using Fighterformations in the greatest strength of whichcircumstances will permit, and, in theDunkerque fighting, where we could chooseour time and build up our formations on theoutward journey, I habitually employed four-Squadron formations as a preferable alternativeto using two-Squadron formations at more fre-•quent intervals; but, during the attacks onLondon, the available strength of Fighters didnot admit of this policy, nor was time avail-able.

202. 'I quote from Air Vice-Marshal Park'sreport:—

" The general plan adopted was to engagethe enemy high-fighter screen with pairs ofSpitfire Squadrons from Hornchurch andBiggin Hill half-way between London andthe coast, and so enable Hurricane Squadronsfrom London Sectors to attack bomberformations and their close escort before theyreached the line of fighter aerodromes Eastand South of London. The remainingSquadrons from London Sectors that couldnot be despatched in time to intercept thefirst wave of the attack by climbing in pairsformed a third and inner screen by patrollingalong the lines of aerodromes East andSouth of London. The fighter Squa'dronsfrom Debden, Tangmere, and sometimesNortholt, were employed in wings of threeor in pairs to form a screen South-East ofLondon to intercept the third wave of theattack coming inland, also to mop up retreat-ing formations of the earlier waves. TheSpitfire Squadrons were redisposed so as toconcentrate three Squadrons at each of Horn-church and Biggin Hill. The primary r61eof these Squadrons was to engage and driveback the enemy high-fighter screen, and soprotect the Hurricane Squadrons, whose taskwas to attack close escorts and then thebomber formations, all of which flew at muchlower altitude."203. I think that, if the policy of big forma-

tions had been attempted at this time in No. 11


Group, many more Bombers would havereached their objectives without opposition.

204. Air Vice-Marshal Park also quotes theresults of the ten large formations ordered fromDuxford into No. u Group in the last half ofOctober, when the Germans were employingFighter-types only. Nine of these sorties madeno interception, and the tenth destroyed oneMe. 109.

205. The most critical stage ̂ of,1;the Battleoccurred in the thud phase. On the I5thSeptember the Germans delivered their maxi-mum effort, when our Guns and Fighters to-gether accounted for 185 aircraft. • Heavypressure was kept up till the 27th September,•but, by the 'endatof the month, it becameapparent that the Germans could no longer facethe Bomber wastage which they had sustained,and the operations entered upon their fourthphase, in which a proportion of enemy Fightersthemselves acted as Bombers.

206. This plan, although the actual damagecaused by bombs was comparatively trivial, wasaimed primarily at a further whittling downof our Fighter strength, and, of all the methodsadopted by the Germans, it was the mostdifficult to counter. Apart from the previousdifficulty of determining which formationsmeant business, and which were feints, we hadto discover which formations carried bombs andwhich did not.

207. To meet this difficulty, Air Vice-MarshalPark devised the plan of using single Spitfires,flying at maximum height, to act as Recon-naissance aircraft and to report their observa-tions immediately by R/T.

208. A special Flight was organised for thispurpose, and. it was later recommended that .theSpitfires should be employed in pairs, forreasons of security, and that the Flight shouldbecome a Squadron. A special R/T receivingset was erected at Group Headquarters so thatreports might be obtained without any delay intransmission from the Sector receiving station.There is reason to believe that the Germans alsoadopted a system of using high-flying H.E. 1135as Scouts. Their information concerning ourmovements was transmitted to the ground andrelayed to their -Bombers in the air.

209. In the fourth phase, the apparent ratioof losses in our favour dropped appreciably.I say " apparent" because, in fighting atextreme altitudes, fighters often could not seetheir victims crash, and.the percentage re-ported as Certainly Destroyed was unfairlydepressed. Our own casualties, nevertheless,were such that the C. Category squadrons,which I was hoping to build up to operationalstrength again, remained in their condition ofsemi-effectiveness.

210. Serious as were our difficulties, however,those of the enemy were worse, and by theend of October the Germans abandoned theirattempts to wear down the Fighter Command,and the country was delivered from the threatof immediate invasion.

211. The Order of Battle at the beginning ofNovember is shown at Appendix E. Cate-gories of Squadrons (A, B. or C, vide para-graph 177) are indicated.

212. Increasingly throughout the Battle hadthe importance of a high " ceiling " been mani-fested. It is by no means necessary that every

Fighter ishall have its best performance atstratospheric heights; any such policy wouldresult in a loss of performance at lower altitude,and we must never lose sight of the basicprinciple that the Fighter exists for the purposeof shooting down Bombers, and that its en-counters with other Fighters are incidental tothis process.

213. There are, nevertheless, arguments forgiving to a percentage of Fighters a ceiling(determinable by specific physiological tests)above which no enemy can climb without theuse of Pressure Cabins. Just as the " WeatherGauge " was often the determining factor inthe tactics of sailing ships, so the " HeightGauge" was often crucial in air combat.Exhaust-driver turbo-superchargers 'have cer-tain advantages over gear-driven blowers atgreat height, and should be considered foradoption in spite of their disadvantages.

214. It must be remembered also that theinitiative always rests with the Bomber, whocan select at will the height at which he willmake his attack. We must be prepared, there-fore, for the appearance of the pressure-cabinBomber, flying at a height unattainable by anynon-pressurised Fighter. (I should perhapsexplain that there is a height, about 43,000 feet,above which the administration of any quantityof oxygen at atmospheric pressure becomes in-effective because it cannot 'be inhaled arid apressure cabin or a pressure suit becomesessential.) Of course, a pressure-cabin Bomberis inefficient and vulnerable, because it is diffi-cult to operate free guns from a pressure cabin,and pressure leakage from -holes made in thewalls of the cabin will prostrate the crew. Thethreat from pressurised Bombers is thereforeserious only if we have no Fighters to meetthem, and for this reason we should alwayspossess a limited number of pressurisedFighters.

215. Various other If ssons were learned fromthe experience of fighting at extreme altitudes.One very tiresome feature was that a consider-able proportion of ultra-high-flying raids wasmissed by the' Intelligence systems, or reportedso late that time was not available to clim^and" intercept. This made it necessary toemploy standing patrols just below oxygenheight (about 16,000 feet). These patrolsclimbed to intercept at extreme height whenordered to do so. This cut at the roots ofthe Fighter Command system, which was de-signed to ensure economy of effort by keepingaircraft on the ground except when required tomake an interception.

216. Another lesson was that the system ofusing an " Above Guard " should be retainedeven when an attack was initiated from extremealtitude.

217. Flying and fighting-fatigue increaseswith altitude, and the comfort of the pilot re-quires unremitting attention. Cockpit heatingand the meticulous pursuit and elimination ofair leaks are of great importance. Attentionshould also be paid to the elimination of icingon cockpit hoods (which are apt to freeze im-movably) and on the inside and outside ofwindscreens.

218. A serious handicap, which I have nothitherto mentioned, was the fact that the changeover from " High Frequency " to " Very High


Frequency " Radio Telephony was still in pro-gress. The V.H.F. was an immense improve-ment on the H.F., both in range and clarity ofspeech; -but the change over, which had startednearly a year before, was held up by the slowoutput of equipment. This meant that muchwork had to be done on aircraft Radio equip-ment during the Battle, and Squadronsequipped with V.H.F. could not communicatewith H.F. Ground Stations, and vice versa.

219. Some of our worst losses occurred throughdefective leadership on the part of a unit com-mander, who might lead his pilots into a trapor be caugjht while jclimbing by: an enemyformation approaching " out of the sun." Dur-ing periods of intense activity promotions to thecommand of Fighter squadrons should be madeon the recommendation of Group Commandersfrom amongst Flight Commanders experiencedin the methods of the moment. If and whenit is necessary to post a Squadron Leader (how-ever gallant and experienced) from outside theCommand, he should humbly start as anordinary member of the formation until he hasgained experience. Only exceptionally shouldofficers over 26 years of age be posted to com-mand Fighter Squadrons.

220. The experience of the Battle made me alittle doubtful if the organisation of a squadroninto. 2 Flights, each of 2 Sections of 3 aircraft,was ideal. It was, of course, undesirable tomake any sweeping change during the Battle,and I relinquished my Command shortly afterits termination; but the weakness lay in theSection of 3 when it became necessary to breakup a formation in a " Dog Fight." Theorganisation should allow for a break up intopairs, in which one pilot looks after the tailof his companion. A Squadron might bedivided into 3 Flights of 4 (which would limitthe employment of half-Squadrons), or it mightconsist of 2 Flights of 8, each comprising 2 Sec-tions of 4. This latter suggestion would upsetstandard arrangements for accommodation.

221. The matter is not one which can besettled without consultation with various autho-rities and Branches of the Air Ministry. I there-fore merely raise the point without making anydefinite recommendation.

222. A great deal of discussion took place be-fore and in the early stages of the war as tothe best method of " harmonisation " of theguns of an 8-gun Fighter: that is to say thedirection, in relation to the longitudinal axis ofthe aircraft, in which each gun should bepointed in order to get the best results.

223. There were three schools of thought: —One maintained that the lines of fire should

be dispersed so that the largest possible" beaten zone " might be formed and onegun (but not more than one) would alwaysbe on the target.

The second held that the guns should be leftparallel and so would always cover an elon-gated zone corresponding with the vulnerableparts of a Bomber (Engines, Tanks and Fuse-lage).

The third demanded concentration of thefire of all guns at a point.224. Arguments were produced in favour of

all three methods of harmonisation, but in prac-tice it was found that concentration of fire gavethe best results. Guns were harmonised so thattheir lines of fire converged on a point 250 yards

distant: fire was therefore effective up to about500 yards, where the lines of fire had openedout again to their original intervals after cross-ing at the point of concentration.

225. It was very desirable to get data as tothe actual ranges at which fire effect had beenobtained. The Reflector Sight contained arough range-finder which the range of an air-craft of known span could be determined if itwas approached from astern, but, in spite ofthis, pilots, in the heat of action, generallyunderestimated the ranges at which they fired.

226. Cinema guns, invaluable for trainingpurposes, were used in combat also; and manystriking pictures were obtained, from whichvaluable lessons were learned.

227. The types of ammunition used in theguns varied during the course of the Battle.It was necessary to include some incendiary am-munition, but the type originally available gavea distinct smoke-tracer effect. Now tracer am-munition in fixed guns at any but very shortrange gives very misleading indications, and Iwished pilots to use their sights properly andnot to rely on tracer indications. (The aboveremarks do not apply at night, nor to free guns,where tracer is essential for one of the methodstaught for aiming.)

228. During the Battle " de Wilde " am-munition became available in increasing quan-tities. This was an incendiary ammunition with-out any flame or smoke trace, and it was ex-tremely popular with pilots, who attributed toit almost magical properties. 8-gun Fighters,of course, were always liable to be sent up atnight, and it was therefore desirable to retainsome-of the older types of incendiary bullets.These were preferred to the " tracer " proper,which gave too bright a flame at night.

229. A typical arrangement, therefore,was: —

Old-type incendiary in the 2 outer guns,de Wilde in one gun while supplies were

limited,Armour piercing in 2 guns, and ball in the

other 3.230. A discussion on the offensive and de-

fensive equipment of aircraft will be found inAppendix F. It will be of interest to all con-cerned with the Design of Technical Equipmentof Aircraft.

PART III.—NIGHT INTERCEPTION.231. No. story of the Battle would be com-

plete without some account of the Night opera-tions. It is true that they constituted only asubsidiary activity in comparison with the mainGerman objective of fighting us to a standstillby day so that Air Superiority might be attainedas a preliminary to Invasion. The night attacksdid little directly to affect the efficiency of theDay Fighting Squadrons, though they had cer-tain indirect effects. Although actual casualtieswere insignificant, disturbance and loss of sleepwere caused; damage was done to factorieswhere aircraft engines and accessories were pro-duced; and the stress of continuous operations,day and night, imposed a very heavy strain onFormation Commanders and Staff officers, andupon the personnel of all Operations Rooms.

232. I had long been apprehensive of theeffect of Night attacks, when they should begin,and of the efficacy of our defensive measures.


23*3- We relied on daytime interceptionmethods, and on the Searchlights to illuminateand hold the Bombers. If they were capableof doing this, all would be well, since the dis-tance at which an illuminated Bomber can beseen by night is comparable with the range ofvisibility by daylight.

234. The first night attack worthy of thename was made early in June and the resultswere encouraging. Aircraft were well pickedup and held by the Searchlights and 6 wereshot down. The attack was, however, made atcomparatively low altitudes (8,000-12,000 ft.)and the Germans, profiting by this lesson, re-sorted thereafter to greater heights at which theSearchlights were practically ineffective. Inclose consultation with myself, General Pile triedevery conceivable method of operation, butwithout material success.

235. About this time Radio Location instru-ments were fitted in Blenheims and it becamenecessary to develop at high pressure a systemof operation which should enable Night Fightersto make interceptions even against umlluminatedtargets.

236. The difficulty of this task will be realisedwhen it is considered that it became necessaryto put the Fighter within one or two hundredyards of the Enemy, and on the same course,,instead of the four or five miles which wereadequate against an illuminated target.

237. It may be asked why the Searchlightswere so comparatively impotent when they hadafforded an accessory to successful defence at.the end of the last war. The answer lies partlyin the height factor already discussed, and partlyin the greatly increased speed of the Bomber,which was about three times that obtaining in1914. The sound locator, on which Search-lights mainly relied at this time, naturally regis-tered the apparent position of the source ofsound and lagged behind the target to the ex-tent of the time taken by sound to travel fromthe target to the Sound Locator. When thespeed of the target is low it is comparativelyeasy to allow for this lag, but at the speedsof modern bombers the angular distance whichmust be allowed for in searching is so great thatthe Searchlights were generally defeated.

238. The first thing which appeared obviousto me was that a " sound Plot " track trans-mitted from the Observer Corps with a variableand unpredictable " lag " was good enoughonly for Air Raid Warning purposes and wasmuch too inaccurate to be of use for controlledinterception at night: height indications alsowere little better than guesswork. The RadioLocation apparatus (known as A.I.) fitted intwin-engined fighters had a maximum range of2 or 3 miles, but it was limited by the height atwhich the Fighter was flying. If, for instance,the Fighter was flying at 10,000 feet, groundechoes were reflected from all ranges greaterthan this, and an aircraft echo from 10,500 feetwould be indistinguishable among the groundechoes.

239. The minimum range of the A.I. was alsorestricted at this time to about 1,000 feet. Belowthis distance the aircraft echo was swamped byinstrumental disturbance. Continuous and in-tensive development work was in progress tominimise these limitations.

B

240. No Radio Location apparatus was avail-able at this time for inland tracking, and Iturned for help to the Army, which haddeveloped for use with guns a Radio Locationapparatus known as the G.L. Set. Within alimited range (about 40,000 feet) this set couldgive very accurate position plots, and, more-over, could read height to within plus or minus1,000 feet at average ranges.

241. Although these sets were few in numberand were urgently required for their originalpurpose of gun control, General -Pile realisedthe urgency of our need and made availableabout 10 sets for an experiment in the KenleySector on the usual line of approach of LondonRaiders, which commonly made their landfallnear Beachy Head.

242. The G.L. sets were installed at Search-light Posts, and direct telephone communica-tion was arranged with the Kenley SectorOperations Room. Here a large blackboardwas installed, and the G.L. plots were shown atintervals of about 30 seconds and with a greateraccuracy in height than had before been possi-ble iby any means.

243. The track of the pursuing fighter wasdetermined by means of the R/T DirectionFinding Stations. \

244. Major A. B. Russell, O.B.E., T.A.R.O.,co-operated in the development of this systemin the Kenley Sector. His practical knowledgeand tireless enthusiasm were of the greatestvalue.

245. Promising results were obtained almostfrom the first and numerous instances occurredwhere echoes were obtained on the A.I. sets inthe aircraft. Practical results were, however,.disappointing, partly because the A.I.apparatus proved to be unexpectedly capriciousin azimuth, and partly because the Blenheimwas slower 'than many of the German Bombersand was deficient in fire-power. ManyGermans escaped after an initial A.I. " pick-up " and even after visual contact had beeneffected.

246. The A.I. apparatus was then fitted intothe Beaufighters, which were just beginning toappear in Service. The machines and theirengines suffered from " teething trouble " toan unusual degree, and the adaption of A.I.to a new type was accompanied by certaindifficulties. In addition,, they were operatingfrom a wet aerodrome at Red-hill, and thedevelopment of delicate electrical apparatus,combined with a new type of aircraft andengine, with rudimentary maintenance facilities,was a matter of the greatest difficulty. In ninecases out of ten something would go wrong withthe aeroplane or with the A.I. set or with theR/T Direction Finding apparatus or with theCommunication system before an interceptioncould be made. No. 219 Squadron, underSquadron Leader J. H. Little, were engaged inthis work and operated with great energy andenthusiasm under extremely adverse and diffi-cult conditions.

247. It would, of course, have been desirableto carry out all this development work by daywhen faults would have been much more easilydetected and remedied, but the low rate ofAircraft Serviceability precluded Day-and-Night work, and London was being bombedalmost every night, so that I could not afford toneglect the chance of getting practical results.


These, though disappointing, were not entirelynegligible; several Bombers were shot down inthis area during the experimental period, andmany discovered that tney were pursued andturned back before reaching their objectives.Night Fighting Development work was alsogomg on at the same time at the Fighter Inter-ception Unit at Tangmere in Sussex.

248. A supplementary use was found for theA.I. by the installation of A.I. " Beacons "in the vicinity of Night Flying Aerodromes.These afforded a valuable Navigational aid for" Homing " in cases where any defect occurredin the R/T D/F system.

249. Shortly before I left the Command anew piece of Radio-Location apparatus becameavailable in the shape of the " G.C.I." set withthe Plan Position Indicator. ' This was anInland-Reading Set which showed the positionof all aircraft within its range on a fluorescentscreen as the aerial was rotated.

250. The main advantages of this set werethat it had a longer range than the G.L. setand it was possible to track the Bomber and theFighter by the same apparatus instead offollowing one with the G.L. and the other byR/T D/F. Moreover it was found that insome circumstances the accuracy of theR/T D/F method was inadequate for nightinterceptions.

251. On the other hand, the accuracy ofheight readings by the G.C.I, apparatus wasless than that obtainable with the G.L. I under-stand that this has now been improved.

252. Whatever the exact technical methodof plotting positions and tracks of aircraft, theobject was to place the Fighter behind theBomber, and in such a position that the echoof the latter would show in the Fighter's A.I.set. The Fighter then tried to overtake theBomber until it became visible to the nakedeye.

253. At that time only multi-seaters couldbe fitted with A.I., and therefore, concurrentlywith the Night Interception experiments,methods were tried of using the Searchlights'aspointers for Night Fighters, even if the targetwere out of range of the Searchlight Beam.Experiments were made with the Searchlights in" clumps" to increase their illuminatingpower and the visibility of their beams toFighters at a distance.

254. A small Radio-Location set wasdesigned to fit to the Searchlight itself, so asto get over the time-lag which was such aninsuperable obstacle to the use of Sound

Locators. It is probable that if Searchlightscan substitute the speed of light for that ofsound they may take on a new lease of usefullife.

255. The disadvantage of relying entirely onRadio-controlled methods of Night Interceptionis that " saturation point " is quickly reached,and when mass raids are in progress only alimited number of fighters can be operated.Results obtained in the Spring of 1941 showthat Day Fighters can obtain important resultsin conditions of good visibility, especially ifattention is paid to all methods of improvingthe night vision of pilots.

256. During the Battle the " Intruder"system was initiated on a small scale. Nightfighters without A.I. were sent across to Francein an attempt to catch Bombers .while takingoff from, or landing at, their aerodromes; orto intercept them at points where they habituallycrossed the French Coast.

257. I had to leave the Development of NightInterception at a very interesting stage; but itis perhaps not too much to say that, althoughmuch remained to be done, the back of toeproblem had been broken. The experimentshad, of course, been carried out in a small area,and raiders which avoided the area could ibeintercepted only by previously existing methods;but the possibilities had been demonstrated and'could be applied on a larger scale as soon asthe necessary apparatus was provided.

258. The method is, of course, also applic-able to the day interception of raiders makinguse of cloud cover, which have hitherto provedextremely elusive; and it is not too much tohope, that the eventual development of veryhigh-frequency A.I. may enable accurate fireto be opened against unseen targets, so that noteven the darkest night nor the densest cloudwill serve as a protection to the Raider.

259. The day may come when every Single-Seater Fighter is fitted with A.I., but this isnot yet feasible. What can be done is to fit allSearchlights with Radio-Location apparatus sothat every Searchlight Beam' is a reliable pointertowards an enemy, even if the range is too greatfor direct illumination.* If then the Fightercan be informed in addition of the height ofthe Raider, Day Fighters will be able to joinusefully and economically in night operationson dark nights.

* As a result of the experience gained during thisperiod, all searchlight equipments have since beenfitted with Radar control. This, combined withintensified training, has made them, since 1941,extremely accurate.

Squadron.87

21392

234

APPENDIX "A."

FIGHTER COMMAND.

Order of Battle, 8th July, 1940.

No. 10 GROUP.

War Station.ExeterExeterPembreySt. Eval

Type of Aircraft.Hurricane.Hurricane.Spitfire.Spitfire.

SUPPLEMENT TO THE LONDON GAZETTE, n SEPTEMBER, 1946

APPENDIX "A."—con*.

43145601

FIU Unit64

6i5245in5oi600

79610325465745625

604609236

No. ii GROUP.

TangmereTangmereTangmereTangmereKenleyKenleyHawkingeCroydonCroydonManstonBiggin HillGravesendBiggin HillRochfordHornchurchHornchurchNorth WealdMartleshamNorth WealdNortholtNortholtNortholtMiddle Wallop

Hurricane.Hurricane.Hurricane.Blenheim.Spitfire.Hurricane.Hurricane.Hurricane.Hurricane.Blenheim.Hurricane.Spitfire.Hurricane.Spitfire.Spitfire.Spitfire.Hurricane.Blenheim.Hurricane.Hurricane.Blenheim.Spitfire.Blenheim.

A264

8517

4623

26622966

253222

No. 12 GROUP.

Duxf ordDuxfordDebdenDebdenDigbyDigbyDigbyWitteringWitteringWitteringColtishallKirton-in-LindseyKirton-m-Lindsey

Spitfire.Defiant.Hurricane.Hurricane.Blenheim.Spitfire.Hurricane.Blenheim.Spitfire.Hurricane.Spitfire.Hurricane.Spitfire.

Squadron.

21915272

249616603141602603

3504

B

No. 13 GROUP.

War Station.CatterickCatterickAcklingtonAcklingtonLeconfieldLeconfieldTurnhouseTurnhouseDremMontroseWickWick

Type of Aircraft.Spitfire.Blenheim.Spitfire.Spitfire.Hurricane.Spitfire.Spitfire.Defiant.Spitfire.Spitfire.Hurricane.Hurricane.

Group.10 Group

11 Group12 Group13 Group

NON-OPERATIONAL SQUADRONS.(Forming or reforming.)

Squadron.238

i (Canadian)25724273

605607263

Aerodrome.Middle WallopMiddle WallopHendonColtishallChurch FentonDremUsworthGrangemouth

Type of Aircraft.Hurricane.Hurricane.Hurricane.Hurricane.Hurricane.Hurricane.Hurricane.Hurricane.


APPENDIX " C."

6TH A.A. DIVISION, JULY-OCTOBER 1940.

(Note.—This report relates only to 6th A.A.Division. It does not cover the operations ofA.A. Command as a whole.)

Glossary of Abbreviations.H.A.A Heavy Anti-Aircraft.L.A.A Light Anti-Aircraft.G.O.R Gun Operations

Room.A.A.L.M.G. ... Anti-Aircraft Light

Machine-Gun.V.I.E Visual Indicator

Equipment.G.P.O. Gun Position Officer.G.L Radio Location Set

for Gun Laying.V.P Vulnerable Point.F.A.S Forward Area Sight.S.O.R Sector Operator's

Room.G.D.A Gun Defended Area.

i. Layout of A.A. Defences.(a) The area covered by 6th A.A. Division

coincided: with the R.A.F. sectors Debden,North Weald, Hornchurch, Biggin Hill andKenley (i.e., the major part of No. n FighterGroup, R.A.F.). Thus the coastal boundaryextended from Lowestoft (exclusive) in theNorth to Worthing (exclusive) in the South;the internal boundary marching with that ofthe Metropolitan area.

(b) Distribution of A.A. defences was brieflyas follows:—

(i) H.A.A. Guns.The Divisional area contained four main

" gun defended areas " at Harwich, Thamesand Medway North (guns emplaced along theNorth bank of the Thames Fjstuary), Thamesand Medway South (guns emplaced along theSouth bank of the Thames Estuary and de-fending Chatham and Rochester) and Dover(including Folkestone). In addition, H.A.A.guns were deployed for the defence of certainaerodromes.

Each " gun defended area " was based ona Gun Operations Room: at Felixstowe, Vange,Chatham and Dover respectively. ThisG.O.R. was connected directly to n FighterGroup Operations Room at Uxbridge, fromwhich it received plots of enemy raids, whichwere in turn passed down to all gun sites.

The armament of each H.A.A. site consistedof the following: 4 (sometimes 2) 4.5, 3.7 or3-inch guns with predictor. Appendix " A "shows the H.A.A. defences as at the beginningof August 1940 and the end of October 1940.

(ii) L.A.A. Guns.45 Vulnerable Points in the Divisional area

were defended by L.A.A. guns. These V.Ps.consisted of Air Ministry Experimental Stations,Fighter Aerodromes, Dockyards, Oil Depots,Magazines, Industrial Undertakings andFactories.

Armament consisted of the following guns:40-mm. Bofors (with Predictor No. 3 andForward Area Sights), 3-inch, 20 cwt. (CaseI), A.A.L.M.G. and 20-mm. Hispano. Appen-dix " B " shows the V.Ps. with their arma-ment as in August and October 1940.

(iii) Searchlights.Searchlights were deployed in single light

stations at approximately 6,000 yards spacingthroughout the area, but with a closer spacingin certain instances along the coast and in" gun defended areas" where the distancebetween lights was approximately 3,500 yards.

These lights were deployed on a brigadebasis following R.A.F. sectors, and each lightwas connected by direct telephone line and/orR.T. set No. 17 to Battery Headquarters viatroop H.Q. and thence to an army telephoneboard at the R.A.F. Sector Operations Room.• The equipment of a Searchlight site con-sisted of the following:—

go-cm. Projector with, in most cases,Sound Locator Mk. III. In some instancessites were equipped with Sound LocatorsMk. VIII or Mk. IX. During the lateSummer and Autumn the number of Mk.VIII and Mk. IX Sound Locators graduallyincreased, and V.I.E. equipment and 150-011.Projectors were introduced. Each Search-light site was equipped with one A.A.L.M.G.for use against low-flying aircraft and forground defence.

2. Enemy Tactics.(a) High Level Bombing Attacks.

These took place generally between heightsof 16,000/20,000 feet. Bombers approachedtheir targets in close protective formations untilrunning up to the line of bomb release, whenformation was changed to Line Astern (if therewas a definite objective to the attack). Attacksfrequently occurred in waves, each wave flyingat approximately the same height and on thesame course. On engagement by H.A \. guns,avoiding action was taken in three stages:—

Stage i.—The bombers .gained heightsteadily and maintained course and forma-tion.

Stage 2.—Formations opened out widelyand maintained course.

Stage 3.—Under heavy fire, formationssplit and bombers scattered widely on dif-ferent courses. It was after this stage hadbeen reached that the best opportunity wasprovided for fighters to engage.

(b) Low Level and Dive Bombing Attacks.In the latter stages of the enemy air offensive

numerous instances of low level and dive bomb-ing attacks occurred, in particular againstfighter aerodromes (Manston, Hawkinge,Lympne, Kenley).

L.A.A. and H.A.A. employed in dealing withthese forms of attack met with varying success,but in cases where no planes were broughtdown the effect of fire from the A.A. defencealmost invariably disconcerted the dive bomberso that few bombs were dropped with accuracy.

Considerable efforts were made by Me. log'sand Ju. 87*5 to destroy the balloon barrageat Dover, and, though at times they partiallysucceeded, excellent targets were provided forthe Dover H.A.A. and L.A.A. guns.

3. Part played by H.A.A. Guns.Targets of all types presented themselves to

H.A.A. sites, ranging from solid bomber for-mation to single cloud hopping or divebombers, balloon strafers or hedge hoppers, allof which were successfully engaged by appro-priate method of fire.


The action of the defence achieved successin the following ways:—

(a) The actual destruction or disablementof enemy aircraft (see Appendix "C").

(b) The breaking up of formations, thus•enabling the R.A.F. to press home attackson smaller groups of bombers.

(c) Destroying the accuracy of theirbombing by forcing the enemy aircraft totake avoiding action.

(d) By pointing out to patrolling fightersthe whereabouts of enemy formations bymeans of shell bursts.The following methods of fire were in opera-

tion at this period:—

(a) Seen Targets.(i) Each gun site was allotted a zone of

priority and responsibility for opening fire ona target rested with the G.P.O.

(ii) Targets could be engaged by day ifidentified as hostile beyond reasonable doubtor if a hostile act was committed. By night,failure to give recognition signals was an addi-tional proviso.

(iii) It was the responsibility of the G.P.O.to cease fire when fighters closed to the attack.(b) Unseen Targets.

Unseen firing at this time was in its infancyand considerable initiative was displayed inevolving methods for engaging targets unseenby day or by night.

The following methods were employed: —(i) Geographic Barrages.

Many forms of barrage were used by differentG.D.As. but all were based on obtaining con-centrations at a point, on a line, or over anarea, through which the enemy aircraft mustfly.

Suitable barrages for lines of approach andheights were worked out beforehand. Approachof enemy aircraft was observed by G.L. and,by co-ordination at G.O.Rs., the fire from eachsite could be controlled to bring a maximumconcentration of shell bursts at the requiredpoint.(ii) Precision Engagements.

Method jl.y-Due to poor visibility or wrongspeed settings searchlight intersections wereoften made without actual illumination of theaircraft. By obtaining slant range from G.L.and following the intersection on the Predictor,sufficient data were available to enable shellsto burst at or near the intersection.

Method B—This provided for engagementwithout searchlight intersections. Continuousbearings and slant ranges from the G.L. werefed into the Predictor and engagement of targetundertaken on the data thus provided. Forsites which were not equipped with°G.L. theappropriate information was passed down fromG.O.R.

It w'll be appreciated that procedure variedwith different Gun Zones, according to circum-stances and the equipment available. It shouldbe remembered that all engagements of unseentargets were subject to the express permissionof the Group Controller at Uxbridge, so thatdanger of engaging friendly aircraft wasobviated.(c) Anti-Dive-Bombing Barrage.

Special barrages against dive bombers wereorganised round the following V.Ps.: HarwichHarbour, Thameshaven Oil Installations,

Tilbury Docks, Chatham Dockyard, SheernessDockyaid, Dover Harbour, Purfleet Oil andAmmunition Depots.

This barrage could be employed at any timeat the discretion of the G.P.O. when he con-sidered that other and more accurate methodswere unlikely to be effective. The barragewas designed for a height of 3,000 feet andassumed a dive angle of 60°. 'It was basedon a barrage circle round each gun site whichwas divided into 4 quadrants in which thebarrages were placed.

The maximum effort from H.A.A. guns wasrequired from the igth August to the 5thOctober, during which time the crews hadlittle rest, continuous 24 'horn's manning beingrequired at Dover, a " duty gun station"system being worked in all areas.

Evidence is available to show how time andtime again enemy bombers would not, faceorp to the heavy and accurate fire put up bygun stations. r Particularly worthy of mentionare two attacks on Hornchurch aerodrome whenon both occasions fighters were on the groundfor refuelling. A.A. fire broke up the forma-tion and prevented any damage to the stationbuildings and aircraft on the ground.

4. Part played by L.A.A. Guns.The targets which offered themselves to L.A.A.

guns were in the main small numbers engagedin dive bombing or low level attacks on V.Ps.•Opportunity usually only offered fleeting tar-gets, and quickness of thought and action wasessential to make fullest use of the targetswhich presented themselves.

Success against targets by L.A.A. guns wasachieved in the following ways: —

(a) The destruction or disablement of'enemy aircraft (See Appendix " C ").

(6) The prevention of accurate bombingcausing the bombers to pull out of theirdive earlier than they intended.Methods of firing employed by L.A.A. guns

as follows: —

(i) Bofors.Fire was directed either by No. 3 Predictor

or by Forward area Sights; some Bofors werenot equipped with the Predictor when the lattermethod only could .be used.

The Predictor equipped guns require a 130Volt A.C. electric supply which was providedeither from engine-driven generators or fromthe mains. Shooting with the Predictorachieved very great accuracy and the resultsand destruction of aircraft and the averageammunition expenditure .proved the efficiencyof this equipment (see Appendix " C "). TheF.A.S. method permitted quick engagements oftargets although without the accuracy affordedby the Predictor.

(ii) 3-inch 2O-cwt. Guns (Case I).Some V.Ps. were equipped with the 3-inch

20-cwt. gun without Predictor which was firedfrom deflection sights; shrapnel was normallyused. H.E., however, was used for targets atgreater height.

(iii) A.A.L.M.G.Lewis Guns on A.A. mountings proved ex-

tremely effective in attacking low-flying enemy'aircraft. These guns were mounted in single,double or quadruple mountings and were firedby the Hosepipe method using tracer ammuni-tion.

SUPPLEMENT TO THE LONDON GAZETTE, n SEPTEMBER, 1946

(iv) Hispano ZQ-mm. Equipment.A few of these weapons only were deployed

and, owing to shortage of ammunition andlack of tracer, were not found very effective.

5. Part Played by Searchlights.

(a) Day.•Owing to the close spacing of Searchlight

sites they formed a valuable source of intelli-gence and rapid reports were able to be madeupwards of casualties to friendly and enemyaircraft, pilots descending by parachute andother incidents of importance. In addition,they have 'been able to provide valuable reportsof isolated enemy aircraft, trace of which hadbeen lost by the Observer Corps.

The value of the A.A.L.M.G. with whicheach site was equipped cannot be too highlystressed, and during the 4 months under re-view no less than 23 enemy aircraft weredestroyed, confirmed, by AlA.L.M.G. atSearchlight sites -(this includes a few in whichA.A.L.M.G. at H.A.A. sites also shared).Prisoner of War reports showed that it was notgenerally known by the German Air Forcepilots that Searchlight sites were equipped withA.A. defence.

(b) Night.Tactical employment of Searchlights at night

was by either—(i) 3-beam rule, in which 3 sites only

engaged the target; or(ii) by the Master-beam system, in which

one Master beam per three sites exposedand was followed by the remaining twobeams acting under the orders of the Master•beam. °The decision to engage was the responsibility

of the Detachment Commander, and no directtactical control was exercised from BatteryHeadquarters.

In the early stages of the Battle of Britainnight activity was on a small scale and Search-lights had few raids to engage. Some illumina-tions were effected, but throughout it was diffi-cult, by ground observations, to assess theactual numbers. Frequently illuminations werereported by sites not engaging the targets. Thedifficulty of illumination was increased as thenumber of night raids increased, owing to thedifficulty of sites selecting the same target.

There is evidence to show that Searchlightactivity, whilst being difficult to measure, forcedenemy aircraft to fly at a greater height thanthey would otherwise have done. Bombs werefrequently dropped when enemy aircraft wereilluminated, which were possibly intended todiscourage Searchlights from exposing.Evasive tactics by fthe enemy consisted ofchanging height and speed continuously toavoid being illuminated rather than a violentevasive action upon illumination.

6. G.L. Equipment.At the beginning of August experiments had

just been completed to determine whether G.L.equipment could satisfactorily be used as aShips detector. Apart from the results of thisexperiment three other facts emerged:—

(a) The G.L. principle was of considerablevalue when used in conjunction with Search-lights.

(6) That G.L. sets sited in an anti-ship role,i.e., on the top of a cliff, were of consider-able value in detecting low-flying aircraft.

(c) It showed the value of small R.D.F.detectors within the main R.A.F. chain, inplotting enemy aircraft direct to sectors.At the beginning of the Battle of Britain,

21 G.L. sets were in use by 6th A.A. Division,and by October this number had been increasedby another 14.

(i) G.L. at Gun Stations.The main function of these equipments was

to provide data for Unseen target engagementsas described above. One other function of thesesets is worth special mention.

Two sets were specially sited on the cliffsat Dover to pick up targets at low level. Thesesets were able to register aircraft taking offfrom the aerodromes immediately behindCalais, thereby obtaining information consider-ably earlier than could be provided by themain R'.D.F. station on the coast. This in-formation was reported back to OxbridgeOperations Room by a priority code messagewhich indicated the approximate number ofaircraft which had taken off and their position.This report was received some 5/6 minutes be-fore it could be received through the usualR.D.F. channels, and therefore enabled theController to order his Fighters off the groundcorrespondingly earlier than would otherwisehave been the case.

This system, which was also adopted some-what further along the coast in the neighbour-hood of Beaclry Head, was of all the morevalue as the enemy were heavily bombing theR.D.F. stations, which were consequentlysometimes out of action.

(ii) G.L. Stations with Searchlights.During the latter stages of the offensive,

when the night raids on London commenced,it was realised that the G.L. would be of con-siderable assistance to Night Fighters. An" elevation " attachment to the equipment wasproduced and this enabled height to be ob-tained, which in conjunction with a plottingscheme at S.O.R., enabled Searchlight beamsto be directed more accurately on a target toassist night fighters. The results obtained fromthis were not completely satisfactory, but they

•showed the way to the development of thepresent system.

(iii) Mine-Laying Aircraft.It was found that the experiments conducted

in the iship-detector role could be very satis-factorily applied to detecting mine-laying air-craft which flew in at a height too low to bepicked up., by the C.H. Stations. It enabledaccurate tracks of these aircraft to be keptwhich were .afterwards passed to the NavalAuthorities, -who were then able to sweep upthe mines which had been laid by these air-craft.

7. Statistics.Careful records have been kept of ammuni-

tion expenditure and enemy aircraft shot down,and details are shown in Appendix " C."

The following points are worthy of note:—(a] The total enemy aircraft Destroyed, Con-

firmed Category I by 6th A.A. Division duringthe months July-October 1940, inclusive, was


221; of this total 104 were destroyed on sevendays, thus:—

15 August, 1940 1518 ,, ,, 2224 ,, ,, 103i ., ,, 202 September, 1940 ... 137 M ,, ... 1415 » ,, ... 10

104

(6) A considerable number of enemy aircraftwere claimed as Probably Destroyed andDamaged.

(c) The total amount of H.A.A. expendedwas 75,000 rounds.

(d) The total amount of Bofors ammunitionexpended was 9,417 rounds.

8. Ground DefencePreparations were made by all A.A. defences

to assume a secondary ground defence r61e;Bofors were provided with A/T ammunition,and sited to cover approaches to aerodromes,V.Ps., #c. Certain 3.7 inch guns suitably sitedwere given an anti-ship role, and preparationswere made for barrages to be put on certainbeaches. Under the immediate threat of in-vasion in May 1940, mobile columns of A.A.troops were formed, but these troops revertedto their A.A. rdle before the Battle of Britainbegan.

9. Lessons Learnt.(a) The outstanding lesson learnt from this

intensive air attack was undoubtedly the sound-ness and suitability of the organisation andarrangements of the control and direction ofthe anti-aircraft defences. These measures de-vised in peace time and perfected during theearlier arid quieter period of hostilities, stoodthe severe test with amazing resilience andadaptability. No major alterations in thesystem were indicated or, indeed, were madesubsequent to these operations.* The way inwhich the activities of the anti-aircraft linkedin and were capable of co-ordination with themajor partners in the venture—R.A.F. FighterCommand, No. n Fighter Group, and sectorcommands—is perhaps worthy of special note.

* This ' statement applies only to the higherorganisation, and must not be taken to mean thatno improvements were made in the control anddirection of A.A. gunnery.

(b) Other lessons learnt are by comparisonof minor import. Chief among them was thegreat vulnerability of aircraft if caught byaccurate H.A.A. fire when in close formation.A good instance of this occurred in an actionon the 8th September, when a geschwader of15 Do. 173, flying in formation at 15,000 feet,approached a gun site South of River Thames.The opening salvo from the four 3.7-inch gunsbrought down the three leading aircraft, theremaining machines turning back in disorder,scattering their bombs on the countryside intheir night to the coast. •

The value of H.A.A. fire as a means ofbreaking up bomber squadrons to enable themto be more easily dealt with by our fighters wasdemonstrated on numerous occasions in theThames Estuary.

The importance of A.A. shell bursts as a"pointer" to fighters, even though1 the gunscannot themselves effectively engage theenemy, was also frequently demonstrated.

(c) A somewhat negative lesson was the in-ability of A.A. guns, however well served, tocompletely deny an area to penetration bydetermined air attack. Evidence, however,was overwhelming that accurate fire, apart fromcausing casualties, did impair the enemy's aim,and thus avoid, or at least mitigate, -the damageto precise targets.

(d) A rather unexpected result was the highproportion (about 10 per cent.) of .-planesbrought down by A.A.L.M.G. fire. It is doubt-ful, however, whether with the increasedarmour now carried by enemy aircraft thulesson still obtains.

(e) The value of training in recognition wasrepeatedly emphasised throughout these opera-tions. Fortunately, very few instances offriendly aircraft being engaged occurred. Apartfrom the accuracy of the information as tomovement of aircraft furnished to gun sites,this was no doubt due to a reasonable standardin recognition having been attained.

It was, and still is, continually brought hometo the A.A. gunner that, before all else, hemust not engage a friendly aircraft." With thisthought firmly impressed on the G.P.O., someinstances of late engagement or failure to engageperforce occurred. In some cases, had thestandard of training been higher, to enable theearlier recognition of a machine as " hostilebeyond reasonable doubt," the number ofmachines destroyed would have been increased.

Chelmsford, August 2, 1941.

APPENDIX "C.A."

H.A.A. GUN DEFENDED AREAS AND ARMAMENT.

G.D.A.

T and M North ...T and M. South ...Dover and Manston\VattishamBiggin HillKenleyNorth Weald

August 1940.

4-5-in.

3232

3-7-in.

158

3212

+ 4

3-in.

812°14164 '4

4 + 2

October 1940.

4-5-in.

2428,

>

3-7-in. .,

84

2012

3-in.

7121016442

4

D

4566 SUPPLEMENT TO THE LONDON GAZETTE, u SEPTEMBER, 1946

APPENDIX "C.B."

L.A.A., V.P.'s AND ARMAMENT.

V.P.

Aerodromes.Debden, ...WattishamBiggin HillManstonWest Mailing ...CroydonKenley ...RedhillGravesendShorts (RochesterDetlingEastchurchHawkingeLympneNorth Weald ...MartleshamRochfordHornchurchStapleford

Abbotts

A.M.E. Stations.DarshamDunkirkRyePevenseyBawdseyGreat Bromley . . .Canewdon

Industrial and OilCray fordDartfordNorthfleetGrain (Barges) ...ChelmsfordMurex (RainhamjPurfleetCanvey ...Thameshaven ...Shellhaven

Naval.ChathamChattendenSheernessLandguardWrabnessParkeston QuayDoverTilburySouthend Pier . . .

August 1940.

4O-mm.

4

342

4

4

——4

342

3

2

333

——3

———2

—

5

_—

A.A.L.M.G.(No. ofBarrels).

312

2

410128

—4

— •—4

12IO8

* 7

7666

——4

8

—— .48

20

1412

48

——————9M

His-sauo.

—————————————————

——

—

——————

—

———

——————

————————•— ~

3-in.tCase I.

——————2

.

22

43

——————4__

Misc.

———————————————————

—————

——

——————————

——————

——i — 2-pdr

October 1940.

4O-mm.

446 „444434422

4

—54452

2

333333

3i

—22

—

_

4

——9

—

A..A.L.M.G.

17834

108

10

——812IO

428

II12

7

—

87

ii21

3ii12

302O163421201612

—8

242822

1523101618~~~

His-mno.

—

—————

——

—32

34

2

4

5

——

4

•— -

3-in-Case I.

—

———

——3

————————————

———————

i

——i

——

2I

3i

3

—i

—————

Misc.

—————

————• —

————

———

——

———————

——————————

——————4A/T

i — 2-pdr.

APPENDIX "C.C."

I.—AMMUNITION EXPENDITURE AND CLAIMS, CATEGORY I.

H.A.A. (seen targets)H.A.A. (barrage and unseen fire)L.A.A. Bofors onlyA.A.L.M.G. (at S.L. and H.A.F. sites)

Expended.

48, MS26,8699,417Not recorded

Destroyed.

161ii47

23

per E/A.

2082,444

200

NOTES :—(i) The above table gives records from September 3, 1939 to November 3, 1940.

(ii) The total enemy aircraft destroyed during the months inclusive July-October was 221.(iii) The following ammunition was expended from September 3, 1939 to June 30, 1940—

H.A.A. ... ° 2,995L.A.A. (Bofors) ... ... ... ... 1,919

(iv) All the enemy aircraft destroyed by L.A.A. (47) have been credited to Bofors for the purpose of theaverage ; in practice, Lewis guns had a considerable share in several of these as well as in two casesHispano (2,941 rounds) and 3-in. Case I (194 rounds),

(v) Bofors average may be still further sub-divided thus :—With Predictor 179 (3,187 rounds)With F.A.S. ... ... ... ... ... 232 (6,230 rounds)


APPENDIX "C.C."—cont.

II.—TABLE SHOWING TYPES OF AIRCRAFT DESTROYED JULY-OCTOBER 1940.

Type. No.HE. Ill 30Do. 17 39Do. 215 14J«. 87 15Ju. 88 19Me. 109 80ME. no 15Unidentified 9

221

III.

Destroyed by day 203Destroyed by night • 18

221

APPENDIX "C.D."

AMMUNITION EXPENDITURE AND ENEMY AIRCRAFT DESTROYED THROUGHOUT- ANTI-AIRCRAFTCOMMAND FOR JULY, AUGUST .AND SEPTEMBER 1940.

Day* \344 r(^s- Per aircraft.•/I - ' -

July 1940—Day* ..Night / (26 a/c =~ 8,935 rds.)

August 1940—Day* \232 rds. per aircraft.Night f (167 a/c = 38,764 rds.)

September 1940—Dayf \I»798 rds. per aircraft.Night / (144 a/c = 258,808 rds.)

* Mainly by day, little night activity.| Including considerable night activity and large expenditure of ammunition by night.

APPENDIX "E."

FIGHTER COMMAND.

Order of Battle, November 3, 1940.

No. 9 GROUP.Squadron. War Station. Type of Aircraft. Category.312 (Czech) Speke • Hurricane C6n Ternhill Spitfire C29 ($) Ternhill Blenheim Night-Flying

No. 10 GROUP.

79 Pembrey Hurricane C87 (£) Bibury Hurricane B

504 .Filton Hurricane C609 Middle Wallop Spitfire A604 ' Middle Wallop Blenheim Night-Flying238 Middle Wallop Hurricane A56 Boscombe Down Hurricane A

152 Warmwell Spitfire A601 Exeter -' -^Hurricane C

87 (£) Exeter ' . Hurricane B234 St. Eval Spitfire C247 (J) Roborough Gladiator C


APPENDIX "E."—-cont

No. ii GROUP.

25

73*7

229615 •302 (Polish)25724946

2644i

603222141

749266

42i (|)605253

219

14521342260223

Debden

Castle CampMartleshamNortholtNortholtNortholtNorth WealdNorth WealdStaplefordHornchurchHornchurchHornchurchRochfordGravesendBiggin HillBiggin HillWest MailingWest MailingCroydonKenleyKenleyRedhill

TangmereTangmereTangmereWest HampnettFord

Blenheim andBeaufighter

HurricaneHurricaneHurricaneHurricaneHurricaneHurricaneHurricaneHurricaneDefiantSpitfireSpitfireSpitfireDefiantSpitfireSpitfireSpitfireHurricaneHurricaneHurricaneHurricaneBlenheim and

BeaufighterHurricaneHurricaneHurricaneSpitfireBlenheim

Night-Flying

Night-FlyingAAAAAAA

Night-FlyingAAA

Night-FlyingAAA

ReconnaissanceAAA

Night-Flying

ANight-FlyingNight-Flying

ANight-Flying

No. 12 GROUP.

Squadron.303 (Polish)61685

151i

26629(1)7264

242310 (Czech)

19

War Station.LeconfieldKirton-in-LindseyKirton-in-LindseyDigbyWitteringWitteringWitteringColtishallColtishallDuxfordDuxfordDuxford

Type of Aircraft.HurricaneSpitfireHurricaneHurricaneHurricaneSpitfireBlenheimSpitfireSpitfireHurricaneHurricaneSpitfire

Category.

CCCCCC

Night-FlyingCCAAA

No. 13 GROUP.

60765

232 (£)263 (*)

i -(Canadian)32 •

610600 (£)4354

600 (£)245

TurnhouseTurnhouseDremDremPrestwickAcklingtonAcklingtonAcklingtonUsworthCatterickCatterickAldergrove

HurricaneSpitfireHurricaneHurricaneHurricaneHurricaneSpitfireBlenheimHurricaneSpitfireBlenheimHurricane

CBCCCCC

Night-FlyingCC

Night-FlyingC

CastletownDyceMontrose

No. 14 GROUP.

HurricaneHurricaneHurricane


APPENDIX "E."—cont.

NON-OPERATIONAL SQUADRONS.

Group.g Group

12 Group

13 Group

Squadron.308 (Polish)306 (Polish)307 (Polish)71 (Eagle)

263 («

Station.BagintonChurch FentonKirton-in-LindseyChurch FentonDrem

Type of Aircraft.HurricaneHurricaneDefiantBuffaloWhirlwind

NOTE.—Two " B " Squadrons, Nos. 74 and 145, had already been thrown into the battle, leaving only twoavailable at the end.

APPENDIX " F."NOTE ON THE OFFENSIVE AND DEFENSIVE

EQUIPMENT OF AIRCRAFT.1. The general principle of. developing the

maximum possible fire power, which isaccepted in all Armies and Navies, must pre-sumably be applicable to Fighter Aircraft, pro-vided that this can be done without undulysacrificing Performance and Endurance.

2. The 8-gun fighter may be said toexemplify this principle, and at the beginningof the war its results were decisive against Ger-man Bombers, which were unarmoured at thattime.

3. Our Fighter pilots were protected againstthe return fire of Bombers by their engines, andby bullet-proof glass and armour, for theirheads and chests respectively.

4. Furthermore, at this time the return firefrom German Bombers was negligible. Theyhad concentrated on Performance as the prin-ciple means of evasion (a false lesson drawnfrom the low speed of the Fighters used in theSpanish War) and the few guns which theycarried were manually controlled, and so badlymounted that they were practically useless.These facts, in combination with the fire powerand armour protection of our own Fighters,made the latter virtually immune to the fireof unescorted Bombers, and their casualties inHome Defence fighting up to the Spring of1940. were quite negligible.

5. The German Bombers had good self-seal-ing tanks, and this was perhaps the only im-portant particular in which they were aheadof us. In our development work we haddemanded that tanks should be " CrashProof " as well as self-sealing, and the drasticconditions, which our experimental tanks hadto meet had made them unduly heavy andcumbrous.

6. So far as our Fighters were concerned,the wing tanks in the Hurricane were removedand covered with a fabric known as " Linatex "which had fairly good self-sealing charac-teristics. The reserve tank in the fuselage wasleft uncovered, as it was difficult of access andit was thought that it would be substantiallyprotected by the armour which had been fitted.During the Battle, however, a great numberof Hurricanes were set on fire by incendiarybullets or cannon shells, and their pilots werebadly burned by a sheet of flame which filledthe cockpit before they could escape by para-chute.

7. The reserve tanks were therefore coveredwith Linatex as a matter of the highest priority,and a metal bulkhead was fitted in front of thepilot to exclude the rash of flame from thecockpit.

8. The Germans soon began to fit fuselagearmour to protect their pilots and crews, butfor some unexplained reason neither side hadfitted armour behind the engines of theirBombers. The back of the engine is much morevulnerable to rifle-calibre bullets than the front,owing to the mass of ancillary equipment whichis there installed. While the back of the enginelies open to attack, the rifle-calibre machinegun remains a useful weapon, and the fact isa fortunate one for us.

9. The application of armour to Bombers didnot, of course, come as a surprise to us, andits implications had long been discussed.

10. Excluding devices such as hanging wires,exploding pilotless aircraft, etc., I have alwaysthought that the courses open to the Fighter,when rifle-calibre machine-gun fire from asternbecomes ineffective, may be summarised asfollows: —

(A) Deliver fire from ahead or from a flank.(B) Pierce the armour.(C) Attack the fuel tanks with incendiary

ammunition.(D) Destroy the structure of the aircraft by

means of direct hits from explosive shells.(E) Use large shells with Time and Per-

cussion fuzes.Discussing these in order: —

ii.—(A) Fire from ahead or from a flank iseffective but difficult to deliver accurately atmodern speeds. Fire from ahead proved veryeffective on occasions during the Battle, butrelative speeds are so high that the time avail-able for shooting is very short, and Fightersgenerally find themselves in a position to de-liver such an attack more by accident thanby design.

12. Beam attack is very difficult to deliveraccurately, owing to the amount of deflectionwhich had to be allowed. The deflection ringon a Fighter's sight allows for an enemy speedof ipo m.p.h., and therefore a full diameteroutside the ring must sometimes be allowed.

13. The method is effective against forma-tions, when the aircraft hit is not always theone aimed at, and certainly the Gladiators inNorway developed this technique with greatsuccess. On the whole, however, Fighterswhich were constrained to this method of attackwould have a very limited usefulness.

14.—(B) The simplest reaction for theFighter is to pierce the armour, but it entailsthe use of bigger calibres. It must be remem-bered also that it is not- sufficient merely topierce the armour, but the bullet must havesufficient remaining velocity to do lethaldamage thereafter. High velocities, in additionto bigger calibres, are therefore necessary,..


15. The -5-inch gun appeared, at first sight,to be the natural successor to the .303 inch, butexperiments showed that the type available tous in the Autumn of 1940 was practically de-feated by the 8-mm. armour carried in theM.E. 109. It was true that the bullet wouldpierce 20-mm. or more of armour in the open,but it was found that the minute decelerationand deflection of the axis of the bullet, causedby its passage through the structure of the fuse-lage, exercised a very important diminution onits subsequent penetrative powers.

16. Experiments carried out with -5-inchguns of higher velocity in America have givenencouraging results, and it is not at presentpossible to dogmatise on the subject. It would,however, be foolish to adopt a gun which couldbe defeated by a slight thickening of the armourcarried by the Bomber and the aim should beto defeat the thickest armour which it is prac-tically possible for the enemy to carry.

17. We have at present no gun of a calibrebetween .5-inch and 20-mm. (.8 inch). Thelatter was originally adopted by the French be-cause it was of about the right size to fire anexplosive shell through an airscrew of a HispanoSuiza engine, and was adopted by us fromthem. If, therefore, it proves to be of the bestweight and calibre for an armour piercing, thatis due to accident rather than design.

18. A study of available data might-lead oneto suppose that a calibre of about 15-mm. wouldbe the ideal, and I understand that this sizehas recently been adopted by the Germans; butwe cannot now start designing a new gun forthis war, and we must choose between the•5-inch and the 20-mm. We shall soon getreliable data from American Fighter types inaction. They have faith in the -5-inch gun.

19. The Armament of the Royal Air Forceis not its strongest point, and in my opinionwe should do our own Design and Experimentalwork, and satisfy our requirements withoutbeing dependent on Woolwich and Shoebury-ness.

20.—(C) Incendiary ammunition may befired from guns of any calibre and Bomber tankshave been set on fire by .303 inch ammunition.The bigger the bullet, however, the bigger thehole, and a small bullet stands a good chanceof being quenched before it can take effect.In any case, the fuel tanks of a Bomber con-stitute so small a proportion of the whole targetthat they cannot be made the sole objective ofattack; and it seems that the adoption of alarge-calibre gun and the use of a proportionof incendiary ammunition therein will afforda satisfactory compromise.

21—(D) It was assumed by the French thatthe 20-mm. shell would be effective against thestructure of modern aircraft. I do not knowwhat trials they carried out, but the tests doneby us at Shoeburyness and Orfordness indicatethat the effect of a 2O-mm. shell exploringinstantaneously on the surface of an aircraft isalmost negligible, except in a small percentageof lucky strikes. The normal effect is that ahole of about 6-inch diameter is blown in thesurface, and that the effect at any distance isnil, since the shell is blown almost into dust.Occasionally the fuze penetrates and does somedamage, but this is slight in comparison withthe total weight of the shell. Even the big37-mm. shell, though it may be spectacular

damage, will not often bring a Bomber downwith a single hit. Greater damage is done ifthe fuze is given a slight delay action, so thatit bursts inside the covering of the aircraft, butsmall delay action fuzes are unreliable in opera-tion and difficult to manufacture, and, on thewhole, it seems doubtful if explosive shells areas efficient as armour-piercing and incendiaryprojectiles, especially as they will not penetratearmour. Another point must be remembered,viz., that a drum of explosive shells is a verydangerous item of cargo: if one is struck anddetonated by a bullet it is not unlikely thatthey will all go off and blow the aeroplaneto pieces.

22.—(E) The use of large shells (comparableto Anti-Aircraft types) from Fighter aircraft ispractically prohibited by considerations ofweight if a gun is used. The gun itself mustbe heavy £nd the structure must bestrengthened to withstand the shock of recoil.The walls and base cf the shell al'.o have tobe made uneconomically heavy to withstand thedischarge. All these difficulties, however, canbe overcome il' the Rocket principle is used.It is true that a Rocket can be dischargedonly in the direct line "of flight, but that is noparticular handicap to a Fighter. It can havea light firing tube, there is no recoil, and theshell can be designed for optimum fragmenta-tion effect. (I have been told that a 3-inchRocket shell develops the same explosive andfragmentation effect as a 4.5-inch Anti-Aircraftgun shell). It also starts with an advantage

'over the terrestrial rocket in that it has aninitial velocity of about 300 m.p.h. through theair, which gives it enhanced accuracy. Forthis weapon a " Proximity Fuze " would beideal, but, pending the development of this,there is no reason why the Rocket should not beused with a Time and Percussion Fuze used inconjunction with a range-finder in the Aircraft.

23. This item was put on the programmeabout 7 years ago, and I think it a great pitythat it was allowed to drop. True, unexpecteddifficulties may be encountered, and nothingmay come of the project, but it is an importantexperiment, and our knowledge of what is andis not possible will not be complete until ithas been tried.

24. I think that our decision to adopt the2O-mm. gun is probably the wisest which wecould have taken, but to carry increased loadefficiently something bigger than the Hurricaneor Spitfire is needed. The Typhoon with2,000 h.p. should be ideal when it has beengiven an adequate ceiling.

25. In the meantime the Hurricane must besomewhat overloaded with 4 Cannons, andmixed armament (2 Cannons and 4 Brownings)in the Spitfire is merely a compromise neces-sitated by loading conditions. Might not thehigh-velocity American -5-inch gun prove asuitable armament for the small fighter?

26. As regards ammunition for the 20-mm.gun, the so-called " solid " bullet was merelya cheap steel bullet produced by the French forpractice purposes. Its mass and velocity haveenabled it hitherto to smash through armourto which it has been opposed, but an improveddesign will probably be needed before long;doubtless the matter is receiving attention. Iunderstand that the incendiary bullet-^-theequivalent of the de Wilde -303-inch—has beengiving good results.


27. One. other attribute of a naked steel bulletmust not be overlooked, viz., its incendiaryeffect "when it strikes a ferrous structure.During ground trials a Blenheim was set on fireby the second hit from a " solid " bullet. Un-fortunately, German aircraft do not normallycontain much iron or steel.

28. If we look into the not too distant future,I think we shall find that an additional andquite different reason may arise for the adoptionof the high-velocity gun with a comparativelyheavy projectile. I refer to the increasing inten-sity and effect of return fire from Bombers.

29. Our Fighters are protected to a verylarge degree from the return fire of Bomberswhich they attack from astern, so long as theyhave to sustain the impact only of rifle-calibrebullets.

30. The situation will be quite different,however, if turrets with .5-inch guns are com-monly u§ed in Bombers. The Bomber has thecomparative advantage over the pursuingFighter of firing '' down-wind " (one may geta clear idea of the situation by imagining bothaircraft to be anchored in space, with a30o-m.p.h. wind blowing from the Bomber tothe Fighter). The result is likely to be thateffective armouring of Fighters against returnfire will be impossible, and fighting ranges ingood visibility may be considerably lengthened.In such circumstances high velocity, flat trajec-tory and a heavy projectile will attain increas-ing importance; attention will also have-to bepaid to accurate methods of sighting, andallowance for gravity drop.

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