Featuring Hay directing alongside the estimable Basil Dearden, Tthe Black Sheep of Whitehall is amongst the comedian's finest pictures. Hay stars as William Davis, the head of a correspondence college who becomes embroiled with the Nazis as they try to prevent the signing of a trade agreement. On learning that a Nazi agent has breached security and is posing as the economics expert responsible for lining out the international agreement, the good professor tries to find the real expert, who has been kidnapped and hidden. In a plot centring on mistaken identities, Hay appears in six different disguises, and twice as a woman. The superb supporting cast includes Sir John Mills and Thora Hird.