Frank Birch

Francis Lyall "Frank" Birch, (5 December 1889 – 14 February 1956) was a British cryptographer and actor. He was educated at Eton College and King's College, Cambridge.

During World War I, he served as a lieutenant commander with the Royal Naval Volunteer Reserve, and served in the Atlantic, the Channel and the Dardanelles before joining the Naval Intelligence Division (Room 40) from 1916 to 1919. Birch wrote a satirical history of Room 40, Alice in ID25. Birch was appointed an OBE in 1919.

He was a fellow of King's College, Cambridge, between 1915 and 1934 and a lecturer in history at Cambridge from 1921 until 1928. Birch left Cambridge to pursue an acting career in the 1930s, including the role of Widow Twankey in pantomime.

In 1939, he was part of a BBC television production in a Teresa Deevy play "In Search of Valour".

He joined the Naval section at Bletchley Park in September 1939, and later became Head of the (German) Naval Section. He had to face the shortage of Bombes to decipher the Naval Enigma, which led to the use of American Bombes via OP-20-G. Birch was awarded a CMG in 1945.