When Rodney Dennys, a counter-intelligence officer working in the feverish atmosphere of The Hague in July 1939 received a phone call from a German agent working for the British and warning that Germany would invade Poland in just over seven weeks time, he insured the message was cyphered back to Britain immediately. In the event the warning was accurate to within days, in spite of a sustained belief that Hitler might still be placated.

Historian Heather Jones explores the document in which Rodney Dennys recalls his intelligence coup and the subsequent inaction of the British authorities. She asks why it was that the Foreign office and leading figures in the Joint Intelligence Committee failed to act on such a detailed warning and she finds out about the German agent, Wolfgang Zu Putlitz who gave it. It was the last in a long series of accurate intelligence reports he'd supplied by way of his link on the British side, a certain Klop Ustinov, father of the famous actor and playwright, Peter.

The programme examines the state of the British intelligence community at the time, the split between appeasers and those who distrusted every German move and why this Document and the later Venlo incident in which two British intelligence officers walked into a trap laid by the Germans, was a Secret Intelligence Crisis.