Not to be confused with the far superior “Agent Z and the Penguin From Mars”, Agent Zigzag is the true story of Eddie Chapman. Chapman was a criminal specialising in blowing up safes before the second world war and was languishing in Jersey prison when the island fell to the Nazis. In a bid to return to the UK mainland (or maybe just to earn some money, his motives are often pretty unclear) Chapman volunteered to spy for the Germans.
He was then left in jail in France while his request filtered through German bureaucracy. After being interviewed by the German secret service he was sprung and trained for sabotage mission to blow up the DeHavilland factory that made the Mosquito. Chapman parachuted into Britain and immediately defected. He was then used to feed inaccurate information to the Germans. MI5 faked the sabotage of the DeHavilland factory to keep his cover intact and Chapman was sent back to the Nazis via neutral Portugal.
Almost as soon as he arrived, Chapman sent a couple of bombs disguised as lumps of coal back home for the secret service to investigate, by suggesting that he smuggle them aboard the British merchant ship that brought him. The Germans then spent some time interviewing Chapman, to try to ensure that he had not been "turned" by the British. Nazi interrogation seemed to comprise mostly of taking Chapman out to expensive bars and restaurants and getting him drunk. If this is accurate, then MI5 are more than welcome to take a crack at me; I like a decent Sauvignon Blanc, Pims, Kier Royale and a cocktail of my own devising made from vodka, Archers and blue flavour Panda Pop.
After a lot of booze, Chapman was sent to Norway where he trained other German spies (passing their details on the the British). As the tide of the war turned against Germany, he was parachuted back into the UK with a mission to find out about secret U boat detection technology (there was no such thing; military intelligence just knew where subs would be due to intercepting their transmissions one the Enigma code had been cracked),radar and to feed back data to help target V1/V2 missiles.
When the war ended, Chapman was dropped by secret service. He wasn't “one of us” and didn't fit in with the public school types runnng the show. And it didn't help that he'd taken up with his criminal friends again. He lived the rest of his life as a crook. There was a film loosely based on Eddie Chapman's lifestory called "Triple Cross". I haven't seen it but I don't have high hopes for it; it's got Christopher Plumber in it. Whatever a book blurb may say, real life is never more incredible than fiction. If I were to rewrite the story, I would have Chapman tortured by the Gestapo, stuff would really get blown up, rather than just faked and I would probably have killed off one of the nicer minor characters (Major Reed, Zigzag’s first handler or Dagmar, his Norwegian girlfriend) for extra pathos. It might be mean, but it makes a better story.