The Jacobean Palace of Apethorpe, a magnificent country house in Northamptonshire, has been sold to a private individual, Jean Christophe, Baron von Pfetten, for the sum of £2.5 million. It will now require many millions to fully restore the property. The new owner is passionate about Apethorpe and is committed to making it a family home for many years to come. The sale also guarantees public access for the next 80 years.

Apethorpe had been on the English Heritage At Risk register since the register began in 1998. Following years of neglect and decay, Apethorpe was at risk of being lost to the nation forever.

On the advice of English Heritage, the Department of Culture Media and Sport (DCMS), compulsorily purchased the house in 2004 and handed it over to English Heritage, with additional grant-in-aid to carry out a major programme of repairs with the utmost care and expertise.

Since we took over, repairs costing £8 million have been carried out and the building now stands in a secure state for the new owner to carry on the good work. Simon Thurley, English Heritage chief executive, warmly welcomed this purchase: "Since 2000 English Heritage has consistently said that the best solution for Apethorpe is for it to be taken on by a single owner, who wants to continue to restore the house and to live in it; especially one who has experience of restoring historic buildings and is prepared to share its joys with a wide public, as Baron Pfetten will do. Apethorpe is certainly on a par with Hatfield and Knole and is by far the most important country house to have been threatened with major loss through decay since the 1950s.

"The purchase price is £2.5m, meaning that English Heritage will have spent a total of £10m saving this architectural masterpiece. In comparison, Salisbury Cathedral received £6m from English Heritage whilst the National Trust received £17.4m from the National Heritage Memorial Fund plus a further £20m from the Heritage Lottery Fund to repair and open up Tyntesfield House. The National Trust has also spent £19.7m on a project at Knole House in Kent, with a £7.75m grant from the HLF and £11m on a project at Castle Drogo in Devon, with a £2.5m grant from HLF. None of these properties were in danger of being lost forever, as Apethorpe was.

"Baron Pfetten has agreed to an 80-year commitment of 50 days public opening a year, a far more extensive undertaking than the normal period of 10 years in the case of English Heritage grant-aided properties. He will also need to fund the comprehensive refurbishment and fitting-out works himself."

English Heritage is the buyer of last resort and although it is rare, has stepped in to save a historic building at extreme risk such as Hill Hall (sold for £2 million in 1999) by reducing the conservation deficit and then selling on to a private developer or owner.

Nick Hill, English Heritage's project manager for Apethorpe, said: "Some of the roofs here were on the point of collapse when English Heritage intervened, which would have led to the loss of some of the finest Jacobean plasterwork in the country. We have made the roofs and structure safe and secure and repaired the plasterwork. We have also cleared away many of the disfiguring modern structures erected in the 1960s when it was a school. But it is right that we left decisions about internal refurbishment and decoration to the future occupier."

Baron Pfetten commented: "My wife and I learnt a lot from the ten years we have spent renovating our 17th century chateau in France. Probably the most important lesson we learnt was to give it all time. Luckily we are young and we have many friends with similar interests keen to support us. My wife and her family are also professional architects who specialise in work to historic buildings. Our vision for Apethorpe is to help this house regain the place in British history that it deserves."

Among England's finest country houses, Apethorpe was begun in the late 15th century. It contains one of the country's most complete Jacobean interiors and hosted 13 royal visits between 1565 and 1636. It has a particularly important place in England's history because of this role it played in entertaining Tudor and Stuart royalty at the pinnacle of its influence around the turn of the 17th century. Its state rooms are arguably the most complete in the country and provide a fascinating window on a rich period of English history.

The architectural importance of Apethorpe lies in the breadth of architectural elements which survive today from almost every period of English architecture since the late 15th century.

Apethorpe is open for pre-booked guided tours during July and August. For more information, visit the prices and opening times page.