Factual error: As Steve McQueen is making his 'great escape', he drives his motorcycle through a gap which a chasing motorcycle and sidecar can't squeeze through, so it crashes. Cut to a crane shot of the retreating McQueen racing into the distance. Keep your eye on the left of frame and into view, on top of a building, is a distinctly un-1940s TV aerial. It's there for a full 7 seconds.
Factual error: When the SS and Gestapo are leaving Bartlett in Von Luger's office on his arrival in the camp, they all give the Nazi salute with bent arms. The correct form was a straight outstretched arm and hand: only Hitler himself was allowed to give the Hitler salute so sloppily.
Factual error: The entrance to tunnel Dick is shown improperly; the trap door was on the side of the drain basin, not the bottom. This was discussed in the Brickhill book, and subsequently verified by research on the site (shown on the US television program NOVA) which found the original door and its lifting handles.