388 Lord Caldecote, U.K. Secretary of State for Dominion Affairs, to Sir Geoffrey Whiskard, U.K. High Commissioner in Australia
Cablegram 179 LONDON, 16 June 1940, 4 a.m.
IMMEDIATE MOST SECRET AND PERSONAL
Mr. Churchill has received Prime Minister's message in Commonwealth Government telegram No. 296  and asks that the following personal message from him should be given to Mr.
Menzies- I am deeply touched by your message, which is only in keeping with all that the Mother Country has ever received in peace or war from Australia.
I do not regard the situation as having passed beyond our strength. It is by no means certain that the French will not fight on in Africa and at sea, but, whatever they do, Hitler will have to break us in this island or lose the war.
Our principal danger is his concentrated air attack by bombing, coupled with parachute and airborne landings, and attempts to run an invading force across the sea. This danger has faced us ever since the beginning of the war, and the French could never have saved us from it, as he could always switch on to us. Undoubtedly it is aggravated by the conquests Hitler has made upon the European coast close to our shores. Nevertheless, in principle the danger is the same. I do not see why we should not be able to meet it. The Navy has never pretended to prevent a raid of five or ten thousand men, but we do not see how a force of say eighty to a hundred thousand could be transported across the sea, and still less maintained, in the teeth of superior sea-power.
As long as our Air Force is in being it provides a powerful aid to the Fleet in preventing seaborne landings and will take a very heavy toll of airborne landings. Although we have suffered heavy losses by assisting the French and during the Dunkirk evacuation, we have managed to husband our air fighter strength in spite of poignant appeals from France to throw it improvidently into the great land battle which it could not have turned decisively. I am happy to tell you that it is now as strong as it has ever been and that the flow of machines is coming forward far more rapidly than ever before; in fact pilots have now become the limiting factor at the moment. Our fighter aircraft have been wont to inflict a loss of two or two-and-a-half to one even when fighting under adverse conditions in France. During the evacuation of Dunkirk, which was a sort of No Man's Land, we have inflicted a loss of three to four to one and often saw German formations turn away from a quarter of their numbers of our planes.
But all Air authorities agree that the advantage in defending this country against an oversea air attack will be still greater because first we shall know pretty well by our various devices where they are coming and because our Squadrons lie close enough together to enable us to concentrate against attackers and provide enough to attack both bombers and protecting fighters at the same time. All their shot down machines will be total losses, many of ours and our pilots will fight again. Therefore do not think it by any means impossible that we may so maul them that they will find daylight attacks too expensive. The major danger will be from night attack on our aircraft factories, but this again is far less accurate than daylight attack; moreover, we have many plans for minimising its effect. Of course their numbers are much greater than ours but not so much greater as to deprive us of a better and reasonable prospect of wearing them out after some weeks or even months of air struggle.
Meanwhile of course our bomber force will be striking continually at their key points and especially oil and oil refineries and air factories and at their congested and centralised war industry in the Ruhr. We hope our people will stand up to this bombardment as well as the enemy. it will on both sides be on an unprecedented scale. All our information goes to show that the Germans have not liked what they have got so far.
It must be remembered that now that the B.E.F. is home and largely re-armed or re-arming, if not upon a Continental scale, at any rate good enough for home defence, we have far stronger military forces in this Island than we have ever had in the late war or in this war. Therefore we hope that such numbers of the enemy as may be landed from the air or by seaborne raid will be destroyed and be an example to those who try to follow. No doubt we must expect a novel form of attack and an attempt to bring tanks across the sea. We are preparing ourselves to deal with these as far as we can foresee them. No one can predict or guarantee the course of a life and death struggle of this character but we shall certainly enter upon it in good heart.
I have given you this full explanation to show you that there are solid reasons behind our resolve not to allow the fate of France, whatever it may be, to deter us from going on to the end. I personally believe that the spectacle of the fierce struggle and carnage in our Island will draw the United States into the war, and, even if we should be beaten down through superior number of the enemy's Air Force, it will always be possible, as I indicated to the House of Commons in my last speech, to send our Fleets across the ocean where they will be protecting the Empire and enable it to continue the war and to blockade materially in conjunction with the United States until the Hitler regime breaks under the strain.
We shall let you know at every stage how you can help, being assured that you will do all in human power [as] we for our part are entirely resolved to do.