One of Marner's early stage roles – as Dracula, with Howard Dean – is still regarded by some as the definitive interpretation of the role. In 1967, well before his role as the German Colonel in Allo 'Allo" Marner played the minor and uncredited role of a German sentry in the classic war film "The Dirty Dozen". His other films include "Ice Cold in Alex", "The One That Got Away", "The Password Is Courage", "You Only Live Twice", "The Boys from Brazil", "The Spy Who Came in from the Cold", "The African Queen" and the Swiss film "Four in a Jeep", in which he did all the Russian dialogue. He was also in the television movie "Birth of the Beatles", as Bruno Koschmider.