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THIS DOCUMENT IS T H E PROPERTY OF H I S BRITANNIC MAJESTY'S GOYERNMEJ

Printed for the War Cabinet. October 1944.

The circulation of this paper has been strictly, limited. It is issued

* V , £ * r * r * ^ - - - - ­for the personal use of S^A^J^Cf f

. T O P S E C R E T " . Copy Ho .

W . P . (44) 600. ­27th October, 1944.

W A R C A B I N E T .

S C A L E O F ^ A T T A C K A G A I N S T T H E - U N I T E D K I N G D O M .

R E P O R T BY T H E C H I E F S OF S T A F F .

W E endorse the a t t a c h e d r e p o r t by the J o i n t In te l l igence Sub-Commit tee on the scale of a i r a t t a c k a g a i n s t t he U n i t e d K i n g d o m . .

2. W e a r e rev iewing the a i r defences of G r e a t B r i t a i n in the l igh t of t h i s r epo r t . 3

(S igned) A . F . B R O O K E . C. P O R T A L . A N D R E W C U N N I N G H A M .

Offices of the War Cabinet, S.W. 1, 27th October, 1944.

[ L L C . (44) 446 (0) (F ina l ) . ] 25th October, 1944.

W A R C A B I N E T . ,

iJoint Intell igence Sub-Committee.

S C A L E O F A I R A T T A C K A G A I N S T T H E U N I T E D K I N G D O M .

- R E P O R T BY T H E J O I N T I N T E L L I G E N C E S U B - C O M M I T T E E .

A S i n s t ruc t ed * we re-assess in t h i s p a p e r the l ikel ihood and possible scale of a i r a t t a c k a g a i n s t t he Un i t ed K i n g d o m . W e do not assess the scale of a t t a c k by flying bombs or o ther long- range weapons .

Overall Strength of the G.A.F. Long-Range Bomber Force. 2. S ince our l a s t p a p e r on th i s sub jec t , ! d a t e d the 28th A u g u s t , 1944, m a n y

u n i t s of the G e r m a n long- range bomber force have been d i sbanded a n d the t o t a l s t r e n g t h of the force has a l r e a d y decl ined f rom 900 to 625 a i rc ra f t , i nc lud ing al l a n t i - s h i p p i n g u n i t s and un i t s engaged in l a u n c h i n g flying-bombs. Moreover,

* J.I.C. (44) 383 (O) Final . f 0 .0 .S. (44) 340th Meeting (O), I t e m 2.;

[28481] e B

nea r ly two- th i rds of the to ta l su rv iv ing force h a s been w i t h d r a w n from opera t ions . The process of dissolut ion a n d the w i t h h o l d i n g f rom no rma l ope ra t ions of the surv iv ing elements a r e expected to cont inue for the following reasons —

(a) P r o d u c t i o n of long-range bombers is s teadi ly decl in ing, a n d h a s now fal len to less t h a n hal f the S p r i n g 1944 figure.

(b) T r a i n i n g of long-range bomber, crews h a s been v i r t u a l l y suspended. (c) The e x p a n d i n g fighter a r m cont inues to r ec ru i t a i r crews from the long­

r a n g e bomber ' force. (d) T h e demand for long- range bombers for l aunch ing flying bombs is

expected to increase the numbers so employed f rom 2 5 - 3 0 to a t least 75-100 d u r i n g the nex t few months , thereby r e d u c i n g the bomber force avai lable for no rma l opera t ions .

(e) Subs t an t i a l numbers of g r o u n d personnel f rom the long- range bomber u n i t s cont inue to be d r a f t ed as rep lacements in A r m y , S.S. a n d p a r a ­chute divisions, as t echnic ians in i n d u s t r y or for the expans ion of the fighter a rm.

(/) G e r m a n y ' s acu te shor t age of av ia t ion s p i r i t has a lmost ce r ta in ly been t h e p r i n c i p a l reason for the v i r t u a l g r o u n d i n g of t h e G e r m a n long­r ange bomber force, bo th on the W e s t e r n a n d E a s t e r n f ronts , for over two months . Even if t he scale of a i r a t t a ck on oil p roduc t ion is somewhat reduced owing to w i n t e r condi t ions , we do not expect a subs tan t i a l increase in the o u t p u t of av ia t ion s p i r i t . P r o d u c t i o n of pe t ro l for the l and forces, and to some ex ten t of fuel for fighter a i r c ra f t , competes w i t h t h a t of fuel for l ong- range bombers. I n view of the more u r g e n t c la ims of the land forces a n d of fighter t r a i n i n g a n d opera t ions , we do not t h i n k t h a t any smal l increase in o u t p u t wi l l resul t in increased al locat ions to the long- range bomber forces.

3. A p a r t from the un i t s engaged in l aunch ing flying-bombs, the only elements o f ' t he long-range bomber force wh ich are l ikely to survive over a per iod a re such special is t u n i t s as those engaged in sea-mining , a n t i - s h i p p i n g opera t ions and a t t a c k s on r a i lways on the E a s t e r n F r o n t . W h i l e these specia l i s t u n i t s may on occasion be al lot ted fuel for p a r t i c u l a r l y i m p o r t a n t ope ra t ions , fuel is only l ikely to be m a d e avai lable to o r d i n a r y long- range bomber- un i t s , so long as they survive, in an emergency for defensive opera t ions in tac t ica l s u p p o r t of the land fighting.

Availability of Forces for attacks on the United Kingdom. 4. Long-Range Bombers.—Since t h e d a t e of our las t r e p o r t t he long-range

bomber force in the W e s t has only opera ted twice, on both occasions in close tac t ica l s u p p o r t of the G e r m a n g r o u n d forces, d u r i n g the defensive emergency at Arnhem. Moreover, i t s s t r eng th has a l r eady decl ined f rom 275 to 50 a i rc raf t , excluding those ope ra t i ng flying-bombs, a n d the re is evidence to sugges t t h a t it wil l decline s t i l l fu r ther . W h i l e theore t ica l ly t h i s force could be re inforced from u n i t s in G e r m a n y a t p resen t non-opera t iona l , t he l imi t i ng fac to rs—set ou t in p a r a g r a p h 2 above—will combine to make any re inforcement ex t remely and increas ingly unl ikely even on a t e m p o r a r y basis .

5. Fighter-Bombers.—While je t -prope l led fighter-bombers m i g h t be made avai lable in small numbers for day l i gh t bombing a t t acks on t h i s count ry , i t ' is unl ike ly t h a t they wi l l in p r a c t i c e be d iver ted f rom the i r o ther a n d more i m p o r t a n t roles in s u p p o r t of the g r o u n d forces a n d in reconnaissance .

Efficiency of the Forces Available. 6. T h e s teadi ly p rogress ing eclipse of the long-range bomber force, t h e wi th­

d r a w a l for the fighter a rm of i t s bes t .c rews , the increas ing lack of ope ra t iona l exper ience and the prolonged per iod of i nac t iv i ty mus t inev i tab ly resu l t in a r a p i d decline in the morale a n d po t en t i a l efficiency of the su rv iv ing elements. N o a t t a c k which they under took a g a i n s t th i s coun t ry would be concent ra ted , nor would i t be pressed home.

Likelihood of Attack against the United Kingdom. 7. I n a d d i t i o n to the shor tage of av i a t i on s p i r i t and the smal l a n d decl ining

size of the long- range bomber force, most of wh ich will be he ld in reserve for

emergencies a n d special tasks , t he fol lowing fac tors wil l also m i l i t a t e a g a i n s t t h e l ikel ihood of a t t a c k s on the U n i t e d K i n g d o m :—*

(a) T h e enemy wi l l a p p r e c i a t e t h a t owing to the inc reas ing p a u c i t y a n d overal l inefficiency of the forces ava i lab le , he could achieve no s t r a t e g i c resul t s .

(b) H a r a s s i n g a t t a c k s can be del ivered by a i r - l aunched flying bombs a t a f a r l i gh t e r cost in a i r c r a f t , a i r crews a n d a v i a t i o n sp i r i t .

(c) A s t he Al l ies ex t end t h e i r hold on the Con t inen t , develop the i r n i g h t ­fighter forces the re a n d d r ive the G . A . F . f u r t h e r E a s t , the r a n g e a t wh ich forces a t t a c k i n g th i s coun t ry wou ld have t o o p e r a t e wi l l increase, they would become more vulnerab le en route t o a n d f rom t h e t a r g e t a n d the efficiency of t he i r a t t a c k s would decrease.

F o r all the above reasons we t h i n k i t un l ike ly t h a t t he G e r m a n s wil l a t t e m p t to bomb any t a r g e t s in the U n i t e d K i n g d o m .

Possible Effect of. Relaxation of the Blackout. 8. I f t he b lackout r e s t r i c t ions were re laxed in London a n d S o u t h - E a s t

E n g l a n d i t is j u s t possible t h a t the G e r m a n s m i g h t a t t e m p t to score a cheap po l i t i ca l v ic tory by m a k i n g one or two e x p e r i m e n t a l bombing a t t a c k s on t h e L o n d o n a rea , in the hope t h a t t h i s would lead to the r e impos i t ion of t h e full b lackout r e s t r i c t ions and. a consequent l ower ing of morale . W e consider i t very doubt fu l whe the r the G e r m a n s would, in p rac t i ce , t h i n k the chances of ach iev ing t h i s resu l t w o r t h the effort. I f the r a id s d i d no t speedi ly lead to a re impos i t ion of the b lackout they would almost ce r t a in ly be abandoned .

Possible Scale of A ttack by Night. 9. Even if the Germans , c o n t r a r y to our belief, d id for a n y reason c a r r y

ou t n i g h t bombing a t t a c k s a g a i n s t the U n i t e d K i n g d o m , the m a x i m u m force employed on any one n i g h t wou ld probably no t exceed 40 a i r c r a f t c a r r y i n g 1-1 to 2 tons each. T h i s scale of effort could not be k e p t u p for more t h a n two n i g h t s in close succession. I n no c i rcumstances need any sus t a ined a t t a c k be expected .

Possible Scale of Attack by Day. 10. A n y d a y l i g h t a t t a c k s would a t most only be occasional a n d would

probably be confined to small-scale sneak r a i d s by je t -prope l led fighter bombers , c a r r y i n g not more t h a n ^ ton of bombs each, a g a i n s t t a r g e t s in S o u t h - E a s t E n g l a n d .

Probable Targets. 11. I f any a t t a c k s were m a d e by long- range bombers, t h e i r t a r g e t would

almost ce r t a in ly be t h e London a rea . E lsewhere , in view of the r a n g e a t w h i c h an a t t a c k i n g force wou ld now have to opera te , t h e r i s k of any a t t a c k W e s t of a l ine r u n n i n g N o r t h a n d Sou th t h r o u g h London is negl igible .

CONCLUSIONS. .

12. W e t h i n k i t unl ike ly t h a t the G e r m a n s wi l l c a r r y ou t n i g h t a t t a c k s on any t a r g e t s in t h e U n i t e d K i n g d o m .

13. W e also t h i n k i t un l ike ly t h a t t he G e r m a n s wil l u n d e r t a k e any d a y ­l i g h t a t t a c k s on the U n i t e d K i n g d o m . A t the mos t such a t t a c k s wou ld only be occasional a n d wou ld probably be confined to small-scale sneak r a i d s by j e t ­prope l led fighter-bombers, c a r r y i n g no t more t h a n ^ - ton of bombs each, a g a i n s t t a r g e t s in S o u t h - E a s t E n g l a n d .

14. I f t he b lackout r e s t r i c t ions w e r e relaxed, in London a n d S o u t h - E a s t E n g l a n d i t is j u s t possible t h a t the G e r m a n s m i g h t a t t e m p t one o r two a t t a c k s on t h e London a r e a in the hope t h a t th i s wou ld lead to t h e r e impos i t i on of t h e full b lackout r e s t r i c t i ons a n d a consequent l ower ing of morale . W e consider i t very doubt fu l w h e t h e r the G e r m a n s would , in p rac t i ce , t h i n k the chances of ach iev ing t h i s resu l t w o r t h the effort.

15. Even if the. Ge rmans , con t ra ry to our belief, d i d for any reason ca r ry ou t n i g h t bombing a t t acks aga in s t the U n i t e d Kingdom, the m a x i m u m force employed on any one n i g h t would probably not exceed 40 a i r c ra f t , c a r r y i n g 1^ to 2 tons each. T h i s scale of effort could no t be k e p t u p for more t h a n two n i g h t s in close succession. A t t a c k s would no t be concent ra ted or pressed home. I n no c i rcumstances need any sus ta ined a t t ack be expected.

16. I f any a t t acks were made by long- range bombers t he i r t a r g e t would a lmost cer ta in ly be the London area . The r i sk of any a t t a ck W e s t of a l ine r u n n i n g N o r t h a n d South th rough London is negl igible .

(Signed) V . C A V E N D I S H - B E N T I N C K . J . A . S I N C L A I R . I . M. R. C A M P B E L L (for D.N.I.). G. W . P . G R A N T (for A.C.A.S:(I.)).

Offices of the War Cabinet, S.W. 1, 25th October, 1944.