Factual error: In the final scene there is a shot which shows a Land Rover in the distance. Land Rovers were not built until after World War 2.
Factual error: When Hauptmann Lutz ditches the radio in the quicksand, it promptly sinks. This is at least debatable, since a radio of that era would've contained a substantial amount of buoyant wood. However, when Sgt. Pugh later throws his incriminating shirt into the quicksand, it is pulled down by a mysterious force. It certainly isn't Archimedes' Principle and looks more like a hidden string to the bottom of the tank on the sound stage.
Factual error: In the closing shots when Van der Poel is being driven away by the Military Police there is a Land Rover parked in front of a building. Land Rovers were not put into production until 1948 so it is seven years too early. (02:03:26)
Factual error: When they are stopped at the military police checkpoint, the MP has brass shoulder titles (RMP) visible, it never became Royal Military Police until 1946, in 1941 it should have been (CMP) Corps of military police.
Continuity mistake: In the final scene of the film, the level of the lager in the glasses varies considerably depending on the camera angle.
Factual error: Several British soldiers are seen carrying Lee Enfield Mk. 4 rifles which were not introduced to general service use at this time.
