I watched this movie on Amazon last night and thoroughly enjoyed it, it's a fictional film based loosely on the true story of a German POW camp in Canada (see Operation Kiebitz)
In this movie during the closing days of World War II, German prisoners riot in a POW Camp in Scotland. Fearful of a mass escape attempt, the British Army sends in an unorthodox Irish Captain in hopes of discovering exactly what is going on. The Irishman at once comes into conflict with the senior prisoner, a U-Boat commander, and the two must match wits, knowing that only one will emerge victorious.
https://www.amazon.co.uk/Mckenzie-Br.../dp/B01AG19KI0