The period of May–June 1940, the months of the fall of France, was a time of the highest stress and instability for all those who lived through it in Europe. By the same token it raised once more the most basic and prominent questions with which decision-makers are ever likely to be confronted – those of war or armistice. It would seem that, as in the previous September, the problem facing British ministers could not have been more conducive to uninhibited debate. The crude facts of physical danger and potential resistance were apparent to all: there existed only a narrow and defined range of available strategies; there could be no question of taking any imaginative initiative such as that of the guarantees of 1939 to transform the political environment. With Hitler in a position of military invulnerability, and with no immediate prospect of attracting new allies by diplomacy, all proposals raised inside the British government would inevitably be subsumed under the crude but clear alternative of fighting on until the situation changed or of coming to terms of some kind with Hitler. Since the War Cabinet met at least once daily,1 it might be thought that in mid-1940 suitable conditions existed for full Cabinet participation in the making of these major political decisions.

Despite these factors, the data present a different picture. It will be argued here that the period in which France left the war demonstrates how an energetic Prime Minister (in wartime necessarily absorbed by military and foreign policy) could lead the opinion of his colleagues into channels of which only he and perhaps a small circle had a very clear advance idea.