From one of our leading experts on disinformation, the incredible true story of the complex and largely forgotten WWII propagandist Sefton Delmer - and what we can learn from him today.

In the summer of 1941, Hitler and his allies ruled Europe from the Atlantic to the Black Sea. Britain was struggling to combat the powerful Nazi propaganda machine, which crowed victory and smeared its enemies.

However, inside Germany, there was one notable voice of dissent from the very heart of the military machine - Der Chef, a German whose radio broadcasts skilfully questioned Nazi doctrine. He had access to high-ranking military secrets and spoke of internal rebellion. His listeners included German soldiers and citizens. But what these audiences didn't know was that Der Chef was a fiction, a character created by the British propagandist Sefton Delmer, just one player in his vast counter-propaganda cabaret, a unique weapon in the war.