I think I know what it is about:
When the Allieds after OP Torch (Landings in Northern Africa) prepared for the next operation in the mediterranean, the landing in Sicily (Operation Husky), they tried successfully to keep the Germans and Italians in the dark about where and when the Allieds would hit next, the Germans knew that something was going on, since the Allieds couldn’t keep the major deployment of troops to northern Africa secret.
One part of this deception was OP Mincemeat.
The body of a 34 year old man, who had died in a British hospital of pneumonia, was dressed as a captain and acting major of the Royal Marines. MI5 and other government agencies created as whole legend about this man, who in reality never existed, but they invented even a fiancee for him, in case the Germans should check on his identity. This body was equiped with paperwork stating that he was a courier on board of a plane carrying important messages to the headquarters of General Alexander in Egypt.
These papers in a secure courier brief case included a plan that the target of the next major Allied operation in the Mediterranean would be a landing in the Balkans with Alexander attacking Corsica and Sardinia as a decoy.
The body was then packed in a cooled special container and loaded on board of a RN submarine in Scotland. The body was then pushed into the sea off the Spanish coast, in a spot, where it was sure to be washed on land.
Spanish fishermen found the body and informed Spanish authorities, who in turn gave all the papers to the German Abwehr, who swallowed the whole think hook, line and sinker. As a result German troops in Greece and Yugoslavia were reinforced, while the Italians were unprepared for the real landings.
http://en.wikipedia.org/wiki/Operation_Mincemeat
http://militaryhistory.about.com/od/navalwarfare/a/mincemeat.htm
It seems that this deception is still working today.
Jan