When Richard Todd is talking to the police outside the run down building that houses Mervyn Johns' flat, there is a peeling poster on the wall advertising the 1955 production of the play "The Remarkable Mr Pennypacker" starring Nigel Patrick and Elizabeth Sellars.
Lionel Meadows:
I said I told you never to lift anything within five miles of around here! Don't you ever learn?
About five minutes into the film, Cummings (Richard Todd) is looking for his stolen car. One of the shots is "flipped" - the sign for "Berger's Cosmetics" reads backwards.
English