William Francis "Nobby" Clarke (1883–1961) was a British intelligence officer and cryptographer of naval codes in both World Wars.
[1] In 1915, he was commissioned as an assistant paymaster, having failed the eye examination for executive officer.
[1] In 1919, Clarke joined the Government Code and Cipher School, working for four years on American diplomatic traffic.
In 1924 he was promoted to head of the new naval section in GC&CS, holding the position to 1941.
He was succeeded as head by his colleague Francis Birch, and then concentrated on Italian naval codes, retiring in October 1945.