M has only been portrayed by 3 actors throughout the length of the series. The only episode that did not feature the head of MI6 was For Your Eyes Only. Well, actually there was a fourth, Edward Fox, who portrayed the character in the unofficial Bond film Never Say Never Again
. Whose version did you like best?
Bernard Lee (11) - Dr. No through Moonraker
Robert Brown (4) - Octopussy through Licence to Kill
Edward Fox (1) - Never Say Never Again
Judi Dench (6) - GoldenEye through Quantum of Solace