Leslie’s long career showed how successful a good jobbing actor can be. Let’s not forget his earlier roles, e.g. in Forbidden Planet http://www.imdb.com/title/tt0049223/, where when the rocket’s engine develops a problem he says “Send in the quantum mechanics” (and this was a serious film) and Night Train to Paris (a seldom seen classic) http://www.imdb.com/title/tt0058402/.