Michael Goodliffe who plays Robie was actually a POW in a German POW camp during the Second World War.
Peter Butterworth was one of the vaulters who covered for the real-life Wooden Horse escape. He auditioned for a part in the film after the war, but was turned down on the grounds that he didn't look convincingly heroic and athletic enough.
Filmed on location in Germany, in a specially reconstructed POW camp, as all the existing ones were still holding displaced persons at the time. (This was only made 5 years after the end of the war.)
Filming was hampered by bad weather, indecision over the ending and other delays. This contributed to the film going significantly over budget. By the time the ending was to be shot, director Jack Lee had left the project so producer Ian Dalrymple completed it.
Finnish visa register number #32530.
The events in this film did indeed take place at the same POW camp (Stalag Luft III) as The Great Escape. However, they occurred in different compounds.
The events on which the film is based took place at the same prisoner of war camp (Stalag Luft III) and at the same time as the events in the much better-known film of the same genre, The Great Escape. The escape committee of prisoners that was planning the latter decided that other escape activity had to be going on at the same time so that life in the camp would appear normal to the Germans. It was the Wooden Horse tunnel that fell into this category.