Britain
Reginald Hall
1870–1943 Director of the Admiralty Intelligence Division from late 1914
Reginald "Blinker" Hall joined the Royal Navy in 1884, became a captain in 1905 and commanded the battlecruiser Queen Mary. In late 1914 he took over the Intelligence Division at the Admiralty and held the post to the end of the war. Its codebreaking office, Room 40, which Sir Alfred Ewing had set up in 1914, deciphered the Zimmermann telegram in January 1917. Hall arranged for the text to reach the Americans in February, and its publication helped draw the United States into the war. He became a rear admiral in 1917 and was knighted in 1918. After the war he sat in Parliament for Liverpool West Derby (1919–1923) and Eastbourne (1925–1929). He died on 22 October 1943.