Winston Churchill, on forming his government in 1940, created the office of Minister of Defence to exercise ministerial control over the Chiefs of Staff Committee and to co-ordinate defence matters. The post was held by the Prime Minister of the day until Clement Attlee's government introduced the Ministry of Defence Act of 1946. The new ministry was headed by a Minister of Defence who possessed a seat in the Cabinet. The three existing service Ministers—the Secretary of State for War, the First Lord of the Admiralty, and the Secretary of State for Air—remained in direct operational control of their respective services, but ceased to attend Cabinet.

Who created the office of Minister of Defence?