HEADQUARTERS FIGHTER COMMAND
ROYAL AIR FORCE,
May 16, 1940
I have the honour to refer to the very serious calls which have recently been made upon the Home Defence Fighter Units in an attempt to stem the German invasion on the Continent.
I hope and believe that our Armies may yet be victorious in France and Belgium, but we have to face the possibility that they may be defeated.
In this case I presume that there is no-one who will deny that England should fight on, even though the remainder of the Continent of Europe is dominated by the Germans.
For this purpose it is necessary to retain some minimum fighter strength in this country and I must request that the Air Council will inform me what they consider this minimum strength to be, in order that I may make my dispositions accordingly.
I would remind the Air Council that the last estimate which they made as to the force necessary to defend this country was 52 Squadrons, and my strength has now been reduced to the equivalent of 36 Squadrons.
Once a decision has been reached as to the limit on which the Air Council and the Cabinet are prepared to stake the existence of the country, it should be made clear to the Allied Commanders on the Continent that not a single aeroplane from Fighter Command beyond the limit will be sent across the Channel, no matter how desperate the situation may become.
It will, of course, be remembered that the estimate of 52 Squadrons was based on the assumption that the attack would come from the eastwards except in so far as the defences might be outflanked in flight. We have now to face the possibility that attacks may come from Spain or even from the North coast of France. The result is that our line is very much extended at the same time as our resources are reduced.
I must point out that within the last few days the equivalent of 10 Squadrons have been sent to France, that the Hurricane Squadrons remaining in this country are seriously depleted, and that the more Squadrons which are sent to France the higher will be the wastage and the more insistent the demands for reinforcements.
I must therefore request that as a matter of paramount urgency the Air Ministry will consider and decide what level of strength is to be left to the Fighter Command for the defences of this country, and will assure me that when this level has been reached, not one fighter will be sent across the Channel however urgent and insistent the appeals for help may be.
I believe that, if an adequate fighter force is kept in this country, if the fleet remains in being, and if Home Forces are suitably organised to resist invasion, we should be able to carry on the war single handed for some time, if not indefinitely. But, if the Home Defence Force is drained away in desperate attempts to remedy the situation in France, defeat in France will involve the final, complete and irremediable defeat of this country.
I have the honour to be,
Your obedient Servant,
Air Chief Marshal,
Air Officer Commanding-in-Chief,
Fighter Command,Royal Air Force.
Source: Dowding Papers
A covering letter from Newell states:
I believe that the point has how been reached where sending more fighter squadrons to France will not affect the outcome of the battle.