Newly declassified letters reveal "inventive" weaponry proposals to help Allied Forces defeat Hitler’s third Reich and the Empire of Japan during World War Two.

Letters in an American archive reveal that the Special Operations Executive (SOE), forerunner to MI6, set up a program to undermine German and Japanese officers in occupied countries by praying them with smelling substance, the Times reported.

Hidden in perfume sprayers, the substance's purpose was "to provide civilian populations with ... a liquid ... [that] will produce unmistakable evidence of extreme personal uncleanliness."

A letter sent by a British military intelligence officer to one of his US counterparts explains the complete plans for a weapon known as “S liquid”, where the S was short for “stench”.