More 1966 'Avengers'. 'How To Succeed At Murder' has Mrs. Peel infiltrate a gang of female assassins who are knocking off their male bosses in order to establish a matriachal society after thousands of years of subjugation. Their leader, of course, is a ventriloquist's dummy named Henrietta.
The chief assassinatrix (I think I've made that word up) is played by Angela Browne. Angela was an intelligent, cultured and very beautiful presence in any number of British films and TV shows from the 1950s onwards, including 'Danger Man' and 'The Prisoner' (as Number 86 in 'A, B or C'), before giving up showbusiness for charity work in 1990. She died in 2001.