We know the story of enigma, but what was the German Alan Turing doing in the heart of the Reich? German codebreakers had similar successes to the Allies, and in this episode, Dan chats to Christian Jennings about cracking codes, the Battle of the Atlantic, and how to use a Romanian Opera Programme to prepare yourself for a war. Christian Jennings has been an investigative journalist, historical, science and current affairs author and war correspondent for over twenty years.