Castle Dyke House is only yards from the spot on Ringinglow Road where he was involved in a 90mph smash with a VW Golf in his £325,000 McLaren-Mercedes in 2005. The former world featherweight champion was jailed for 15 months and later stripped of his MBE after the accident, which broke nearly every bone in 41-year-old Anthony Burgin's body.

Naz, aged 34, his wife Aleasha and their children moved out of Castle Dyke House two months ago to live down south. It is understood they are living near Wentworth in Surrey.

Former colleagues in the boxing world have remarked they have not seen Naz in the city lately. "He's hardly been around Sheffield so he might as well be living on the moon," said one.

Naz has put the house – in 10 acres of lawns with a pond and a field – up for sale through Eadon Lockwood & Riddle, exactly three years after the crash.

He bought the house for £3.5m in 2003 from computer games wizard Jeremy Heath-Smith, the man who launched Tomb Raider Lara Croft.

Chartered surveyor Nick Riddle of ELR, who valued the house jointly with co-director Alistair Humphrey, said he was confident the property would sell for more than last time, despite the credit crunch.

"People at this end of the market don't really feel the recession," he said.

"We have had some interest already. You do phone up people and put them in the know."

The £4m price tag is the most expensive ever in Sheffield. Mr Riddle said there were very few mansions like Castle Dyke House in the area and the mansion had an almost suburban location.

"There are probably only four or five mansions left," he said. "Most have gone for flats developments."

Castle Dyke comes with everything a millionaire could want, including eight bathrooms. It has a magnificent panelled reception hall, a billiards room, gun room, swimming pool, gymnasium and boot room, with an attached coach house with two double bedrooms.There is garage space for six cars and gated security.

Castle Dyke was built in 1900 and at one time was owned by Sheffield Council and used as an old people's home. It was bought in the 1980s by an entrepreneur who converted it back to private use.

Prince Naseem's former gym on Abbeydale Road is now a dress shop, and his website www.princenaseem.com has closed down.