A file of correspondence and reports concerning the appointment of a successor after the death of Admiral Sir Hugh Sinclair ('C'), the head of the Secret Intelligence Service (MI6). Documents in this file include letters nominating various successors; the resumés for two candidates; a report on the personality and abilities of one of the candidates, Commander G. Muirhead-Gould; a letter discussing the effectiveness of MI6’s previous operations, including its penetration of foreign intelligence services; and a letter from the admiralty complaining about shortcomings in cryptography and the lack of intelligence available on the German navy.