Tyringham Hall, the Grade I-listed mansion on the county border with Buckinghamshire, has been put up for sale for an estimated £18 million.
The property, which is midway between Northampton and Newport Pagnell, boasts 25 bedrooms and 32 bathrooms, was built by Sir John Soane, with gardens designed by Sir Edwin Lutyens and was completed in 1797. It has recently undergone a multimillion pound overhaul with the help of English Heritage.
The 18th century neoclassical villa includes four large reception rooms, a kitchen, breakfast room and study on the ground floor, with a spa, games room, cinema room and gym areas on the lower ground.
Crispin Holborow, head of Savills Country Department, believes the house is one of Britain’s finest homes.
He said: “Tyringham Hall combines some of the finest work of Soane and Lutyens, and as such could be labelled as one of England’s greatest architectural masterpieces.
“What’s more, it is in exceptional condition having been beautifully restored.
“It is enormous but also remarkably compact. It has some wonderful formal rooms so can expand into a party home or contract into a family home.
“It is right at the top of English homes, an architectural jewel. It is architecturally and historically significant and this will attract buyers.”