The Black Sheep of Whitehall (the opening credits read Black Sheep of Whitehall) is a 1942 British black-and-white comedy war film, directed by Will Hay and Basil Dearden, starring Will Hay, John Mills, Basil Sydney and Thora Hird in her screen debut.

When he is forced to vacate the office of his debt-ridden correspondence college, 'Professor' Will Davis goes to the Ministry of International Commerce at Whitehall in order to confront his one-and-only student, PR man Bobby Jessop.

The clueless Davis is mistaken for the expert and gets involved in a series of interviews, giving answers based on gambling, con jobs, double entendres or just plain ignorance.

Jessop then discovers that the man he brought with him is in fact Crabtree, a member of a group of fifth columnists working for Nazi Germany.

Having been cleared by the British censors on 27 October 1941,[3] the film premiered at the Regal Cinema by Marble Arch in London on 8 January 1942.