A Second World War conspiracy theory which suggested Nazi deputy fuhrer Rudolf Hess had escaped justice after being replaced with a doppelganger, has finally been debunked after new DNA evidence came to light.

Hess was arrested in 1941 after parachuting in to Scotland to broker peace with Britain, later tried at Nuremberg and incarcerated in Spandau prison Berlin until his death in 1987.

But British doctor Hugh Thomas who worked at Spandau insisted the prisoner purporting to be Hess did not have the correct scars, prompting four inconclusive investigations by the British government.

Now the mystery has finally been solved after a retired military doctor from the US Army and a forensic scientist from Austria tracked down a blood sample from Hess and compared it to relatives still living in Germany.

The results show there is just a one per cent chance that the blood did not belong to the eminent Nazi.

Dr Sherman McCall was working in Walter Reed Army Medical Center in Washington when he first learned that colleague Rick Wahl had once worked at Spandau and had brought back a smear of Hess’s blood to use as a teaching aid.