Gruff, terse boss/commander/ringleader who directs and wields James Bond
(a.k.a. Her Majesty's Secret Service
). In the case of the original one
in the Bond
stories, it was an eponymous code name
; his real name was Admiral Sir
Miles Messervy. M indeed.
In the James Bond films, the part of M has been played by Bernard Lee, Robert Brown, and (presently) Dame Judi Dench.