Continuity mistake: In the final shot, just as the credits are rolling, the British warships are sailing away with the sun setting behind them. In an earlier scene the radio commentator says that the sun is setting and a shot of the sun touching the surface of the sea is shown.
Factual error: Towards the middle of the movie when when the British submarine leaves port with the Man Who Never Was onboard, it is flying what appears to be an American flag. The flag is visible for about ten seconds and if you look closely, you can see the field of blue of the stars and stripes in the upper corner.Marshall Murray
Continuity mistake: In the scene where Robert Wagner and Buddy Ebsen are in a fox hole note the position of the bullets in their boxes. One lot is further away from the pole holding the shade canopy and in a closer shot it's now changed position and closer to the other bullets. The shot then changes again and the bullets are back to their original position as seen earlier. (01:19:25 - 01:20:50)keiko