How a team of sophisticated forgers at an Essex country house fooled the Nazis

From The Great Escape to Secret Army the task of forging documents for runaway PoWs and resistance fighters is portrayed in many a wartime drama as a slow and painstaking one, employing the few ad-hoc materials available in the most difficult of circumstances.

But the British operation to create documents for its agents and allies in occupied Europe was in fact a highly sophisticated affair, run along the lines of a modern same day delivery service.

Indeed, so slick was the work of the forgers that they would often produce a copy of a document from an original stolen from the Nazis and returned before their absence was even noticed.

Yet little has been known about the work of this secretive operation.