
To his personal secretary John Colville the evening before Operation Barbarossa, the German invasion of the Soviet Union. As quoted by Andrew Nagorski in The Greatest Battle (2007), Simon & Schuster, pp. 150–151 ISBN 0743281101
The Second World War (1939–1945)
Variant: If Hitler invaded Hell, I would make at least a favourable reference to the devil in the House of Commons.