The Captive Heart.

A series of stories about the lives and loves of men in a Prisoner of War camp over five years. The main story is of Hasek (Redgrave) a Czech soldier who needs to keep his identity a secret from the Nazis. To do this, he poses as a dead English Officer and corresponds with the man's wife. Other inmates’ stories are also revealed. Location shooting in the British occupied part of Germany adds believability.