Factual error: Throughout the film the British infantry are armed with carbines. These were intended for issue to cavalry and are much shorter than the infantry issue Martini-Henry rifle.
Continuity mistake: Following the shoot out between the Germans and the Greek partisans being aided by the English and American POW's, a German Officer leaps onto a motorbike and takes off into the narrow streets of the village. An American follows on a motorbike and sidecar. Towards the end of the chase the bikes 'jump' over a cart. The German Officer's cap flies off, yet as he tears into a courtyard he has his cap back on.Phillip Churchfield
Continuity mistake: In the scene when the aeroplanes have the dogfight, the German plane is in fact a Spitfire and the two British planes are in fact two Messerschmidt 109's. In the making of the film in Spain, they needed one German and two British planes for the scene, so the only way they could do it was to put British markings on the two Spanish Airforce Me 109's, which they had more of than Spitfires.
Factual error: When they visit "Ireland", presumably the Irish Air Corps aerodrome in Dublin at the time of WWII, all of the staff in the bar at the aerodrome are American servicemen, in neutral Ireland.