In the Second World War, the Germans liked to boast that there was 'no escape' from the infamous fortress and POW camp Colditz. However, the elite British officers imprisoned there were determined to prove the Nazis wrong and get back into the war; since then the fortress became just as famous for its escape attempts. As the officers dug tunnels, removed bricks and got lines of communication to the outside world the Gestapo were determined to uncover their secrets and planted a double agent- Walter Purdy in their midst. It was a race against time for the British officers to expose Purdy for the traitor he was.

Drawn from unseen records, Robert Verkaik tells Dan this extraordinary never-before-told story and tries to make sense of why, despite committing treason, Purdy was able to escape the gallows, not once but twice.

Robert's book is called 'The Traitor of Colditz'.

The producer was Mariana Des Forges and the audio editor was Dougal Patmore

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