He was Britain's most famous Prime Minister, renowned for his love of history, cigars, and fine brandy, but it was Sir Winston Churchill's sweet tooth that lay at the center of a dastardly Nazi plan.

Secret wartime documents recently unveiled reveal a plan hatched by Nazi agents in 1943 to assassinate Churchill with exploding chocolate bars. The scheme involved German bomb makers coating explosives in a layer of rich dark chocolate then wrapping them in expensive-looking black and gold paper. Adolf Hitler then planned to use secret agents working in Britain to smuggle the lethal chocolate along with other luxury items to a dining room used by Churchill and his war cabinet, the Daily Mail reported.

The chocolate bars, branded as "Peters Chocolate" were apparently packed with enough explosives to kill anyone within several meters.

But Hitler's explosive plan was ultimately a dud, foiled by British spies who discovered the plot and notified Lord Victor Rothschild, one of MI5's most senior intelligence chiefs. Rothschild then asked artist Laurence Fish to draw poster-sized images of the chocolate to warn the public to be on the lookout for the bars.

"I wonder if you could do a drawing for me of an explosive slab of chocolate," the letter, written from a secret London bunker and addressed to Fish read. "We have received information that the enemy are using pound slabs of chocolate which are made of steel with a very thin covering of real chocolate."

He continued, "Inside there is high explosive and some form of delay mechanism…When the piece of chocolate is pulled sharply, the canvas is also pulled and this initiates the mechanism."

The letter was discovered by Fish's wife, journalist Jean Bray as she went through his possessions after he died at age 89 in 2009.

Hitler himself was nearly killed by an exploding briefcase on July 20, 1944 as part of a plot by the German resistance to assassinate the dictator dubbed "Operation Valkyrie"