The restoration of any run-down English country mansion is likely to involve extensive re-roofing, re-plumbing and re-wiring. Only one, however, is likely to uncover microphone wires hidden deep within walls by MI6, or involve the polishing of a grand, three-storey oak staircase over which Hitler’s top henchman, dressed in full Nazi regalia, tried to throw himself (failing when he got his leg stuck in the balustrade).

Mytchett Place, between Ash Vale and Frimley Green in Surrey, is a sprawling 23,000 sq ft Victorian house that has just hit the sales market for £15 million. In recent years used as commercial premises, it’s in need of complete renovation, but comes with all the trappings of a trophy home: a sweeping driveway, several huge receptions, at least 12 bedrooms, 11-plus acres and a three-storey tower. However, it’s the house’s fascinating role in one of the second world war’s most bizarre episodes that’s likely to enthral potential purchasers first.

In May 1941, a delusional Rudolf Hess, second in line (after Hermann Goering) to succeed Hitler, flew his Messerschmitt to Scotland in a bid to broker an Anglo-German peace deal that would destroy the Soviet Union. Convinced that Scottish peer the Duke of Hamilton, a pioneering aviator Hess admired, would somehow support him in his mission, he parachuted from 6,000ft on to the moors south of Glasgow.

Picked up by a local ploughman first, Hess was then captured and imprisoned in the Tower of London for a few days, before being taken to Mytchett Place – which became known simply as ‘Camp Z’. Abandoned by the Führer, who declared him insane and stripped him of his medals, Hess was interrogated here by MI6 and examined by psychiatrist Henry Dicks, who declared him a schizoid psychopath.

It wasn’t quite the welcome – or the lodgings – Hess had expected. True, the house had plenty of architectural credibility: with origins in the late 18th century, it was largely built in the 1880s, in Italianate, stucco-fronted style, with a granite-pillared porch, a series of spacious panelled reception rooms on the ground floor, a tower and barrel-vaulted ceilings upstairs. But it was characterised, reported Dicks, by a ‘detective novel atmosphere’.

Taken over by the war ministry, like many other British country estates, Mytchett Place was by 1941 probably the most secure prison in Britain, with Hess being its solitary prisoner – an episode enthrallingly documented by Stephen McGinty in his book Camp Z: How British Intelligence Broke Hitler’s Deputy. A high fence and rolls of alarmed barbed wire surrounded the house, and there were armed patrol officers on duty 24 hours a day in the secluded grounds. In a back room, picking up Hess’s every utterance, snore and sigh through the hidden microphones, sat a stenographer, who reported back to Winston Churchill. Hess was, incredibly, put up in one of the large first floor bedrooms, as opposed to holed up in a dingy basement.

More than 80 years later, you can still see the old guardhouse by the front gates, and positions for machine guns in the grounds. But Mytchett Place has had several other incarnations since, including as headquarters of Frazer-Nash, the British sports car manufacturer founded by Archibald Frazer-Nash, a skilled engineer who designed and produced machine-gun turrets for Wellington and Lancaster bombers. The company – more recently known for its electric and hybrid vehicles ­­– added a modern extension and further outbuildings, as well as a racetrack that was used to test cars.

It’s being sold now, says estate agent Robert Butterworth, director at Jackson-Stops in Woking, with impressive potential to be refurbished and reconfigured back from commercial space into a prime residence, subject to the necessary consents. ‘It has the privacy and seclusion suited to a prime country estate, while being in a well-connected Surrey location,’ Butterworth says. ‘Due to the size of the internal layout, outbuildings and grounds, the possibilities are vast. The racetrack is perfect for adrenaline seekers and Formula 1 fanatics.’

Mytchett Place has already had inquiries from both UK and overseas house-hunters, but whoever buys it will need deep pockets for the refurb – the bill for which is likely run into the millions – and plenty of vision. A commitment to eradicating the ghosts of the past will also help. By the time Hess left the house, after 13 months of interrogations – and with a broken leg from his abortive leap over the staircase – he had been declared in turn neurotic, childlike, paranoid and insane. Later tried at Nuremberg, he would spend the rest of his life in Spandau prison in Berlin, remaining a committed Nazi, hanging himself at the age of 93.

The home is unlisted, but would-be renovators should take care: more secrets from its days as ‘Camp Z’ could well be revealed.