Following the treason of Mathilda Carré, he was imprisoned. After having been offered safety by the Nazis, he was sent as a German agent to England. However, he briefed the British and Polish authorities about the security lapses of his organisation in France and was turned into a double agent using covername Brutus with the Double Cross Committee project. He played a major part in the allied deception prior to the D-Day landing in Normandy in 1944.