"Tweedledum"
This episode won several awards. Wing Commander Marsh, an assistant to the British Medical Officer, decides to use his extensive knowledge of mental illness for an escape. He proposes to "go insane" and be repatriated. Colonel Preston agrees to let him, so long as he follows through with it to the bitter end. Marsh does a very thorough job: his bizarre, disruptive behaviour continually annoys the other allied officers, who remain unaware of the scheme. However, the Germans are not convinced, and Ulmann asks a Corporal to observe Marsh closely. The Corporal has a brother who is insane, so Ulmann believes he is a better judge of Marsh's condition than any doctor. The Kommandant initially refuses to allow the Swiss authority to examine Marsh, but relents when Marsh's evident madness embarrasses him in front of an important visitor. By the time the Germans are willing to consider repatriation, Marsh has done such a convincing job that even the Doctor is uncertain whether or not Marsh is simply pretending to be insane. After Marsh has been successfully repatriated to the UK, it is revealed that his feigned psychosis has become genuine and irreversible, and that he has been committed to a mental hospital for long-term care. Colonel Preston immediately forbids any further escape attempts along the same lines.