Agent Zigzag

I'm reading Ben Macintyre's excellent book, Agent Zigzag, about the British double agent, Eddy Chapman. He was originally recruited by the Abwehr and was trained near Nantes in radio transmitting, parachuting and explosives so that he could be sent to England as a spy for the Germans. Bletchley Park had picked up on Eddy's practice transmissions between Nantes and Paris, knew that his code name was Fritz, that he was probably English and that he was going to land in England at some point. His value to the Germans was highlighted to Bletchley when they cracked a radio transmission saying that Eddy had broken some teeth on a test parachute jump and that the Abwehr had paid 9500 francs for the dentistry bill. Chapman had befriended a pig at Nantes and trained it as his pet, calling him Bobby. Bobby would come running at the sound of Chapman's whistle. The pair would go walking and swimming together. Chapman would radio Paris about Bobby the pig. Bletchley was convinced Bobby was another agent!