M - the code letter for James Bond's boss and fictional head of the British Secret Intelligence Service MI6.
The M in the Bond books is believed to have been based on Rear-Admiral John Godfrey[?] (Ian Fleming's former boss in the Department of Naval Intelligence) and Maxwell Knight[?], former head of counter-subversion in MI5.
The Man Who Was M, Anthony Masters, Basil Blackwell ISBN 0-631-13392-5