Let me tell you a tale.
In April 1943, a body of a young Royal Marines officer washed up on the coast of Spain. Amongst his possessions were two letters from two very high up commanders, hand written and on authentic stationary, casually mentioning the cleaver rouge that they would pretend that they would invade Sicily from Africa, but they would really be sending the Allied forces into Greece and Sardinia. The body was properly buried by the "neutral" Spanish and the letters were carefully copied by the Spanish and passed onto the Nazis before the corpse's personal effects were returned to the British.
Sounds like someone majorly fucked up in allowing such sensitive information to be placed in the hands of Nazis. Or like something out of a work of fiction.
This was actually a very careful and methodic plan, concocted by the Department of Spying and Cleverness in order to deliberately mislead the Nazis into thinking that the Allies would not attack so obvious a target as Sicily.
It was called Operation Mincemeat and it was the single most successful act of deception in the entire war. It made Operation Husky (the invasion of Sicily) a success and saved thousands of lives and is one of the major factors that helped us to win the war.
Sixty years after the plan was thought up of in the secret Rooms 13 and 39 of the Admiralty, the whole truth and the extent of preparation for Operation Mincemeat was carried out successfully, not to mention how much Churchill was relaying on it, has finally been revealed through declassified documents and meticulous research by Ben McIntyre in last year's book Operation Mincemeat.
The book itself is a fascinating and thrilling read and I do highly recommend that you read it. On several occasions as I was reading it at work, coworkers would ask me what the book was about. When I told them, they either said "Oh, so it's fiction, eh?". But it's not. Or, at least, not entirely.
Operation Mincemeat was the brain child of an intelligence officer called Cholmondeley (who went off the hunt locusts in Arabia after the war) and he got the idea from a memo by Ian Fleming (who did intelligence work during the war and got the idea for creating James Bond there) who in turn got the idea from a forgotten 1930's detective novel. So, you see, Operation Mincemeat is not a work of fiction. It is a deliberate work of fiction, to cover up reality, and was based on a work of fiction.
Cholomondeley and his colleague Ewan Montagu (who's brother was the top British spy working for the Soviets) worked deligently for months in order to create "Major William Martin" and make him into a real person. Their work included obtaining a suitable body from a coroner named Bentley Purchase (that's his real name), planting false personal letters, bills and theatre stubs on him (all real and authentic), giving him a personality, girlfriend, photographs and a stuffy father. They also outfitted him with a uniform that had been broken in by Montagu and some underwear that had belonged to a dead Oxford don and finding a submarine to transport the body to a specific point off the coast of Spain where a major Nazi spy just happened to be living and they then announced the death of "Major William Martin" in the Times, ironically in the same edition that also carried the news of the tragic death of Leslie Howard.
All they had to do was sit back and wait to see if the Germans had bought the story and letters hook, line and sinker.
Which they did.
Operation Mincemeat was a success for two reasons.
First, it just so happened that the head of German Intelligence Analysis was a secret anti-Nazi and he probably did see through the web of deception but supported it in his report.
Second, and most importantly, the Nazis did not have a sense of humour. They simply were unable to see the fact that a dead body with some very important information about the Allies' next move had so conveniently dropped into their laps was really a macabre joke told by the British. Indeed, it was the Nazis not having a sense of humour that played a major part in us winning the war.
After the war, Ewan Montagu wrote a book called The Man Who Never Was about the parts of Operation Mincemeat that the government would let him reveal. It was made into a film, which has a few added subplots to make it more entertaining.
There is also a documentary made to tie in with the book Operation Mincemeat. I haven't seen it yet, but it was done by the BBC, so it must be good.