Whittingehame House in East Lothian, which sits in more than 16 acres of landscaped gardens and parkland, was completed for the Balfour family around 1817 by architect Sir Robert Smirke, who designed the main façade of the British Museum in London.

The mansion has a fascinating history. A-listed, it has played host to royals, aristocrats and famous writers, particularly when owned by Lord Balfour, who was Prime Minister from 1902 to 1905.

During his time here, King Edward VII planted an oak tree in the grounds and William Gladstone, Winston Churchill, David Lloyd George, HG Wells and Arthur Conan Doyle all visited.

The Balfour, Whittingehame House, East Lothian

The 1917 Balfour Declaration, outlining British support for a Jewish homeland in Palestine, was reputedly signed in Whittingehame House’s library by Balfour, who was then foreign secretary.

At the start of World War Two, the house became a farm school for Jewish refugee children. In 1963, it was sold by the Balfour family and became Holt School for Boys, which closed in 1980, after which the house was converted to apartments.

The four-bedroom Balfour is the largest of seven in the house, and features 9,000sq ft of accommodation, including a lavish music room and a breathtaking library and billiard room.

Unique features include the conservatory bathroom off the master bedroom, with a luxurious roll-top bath from which you can watch the stars.

A grand summer house has a Neoclassical temple-style veranda.

The apartment also comes with access to all of the landscaped grounds, which is – in the main – for the use of the Balfour’s occupants.

The current owners bought it in 2011, upsizing from another apartment in the mansion. They spent 18 months and more than£1 million on refurbishing the place, including rewiring, replumbing and installing new sash windows.

Mark Cullerton, of estate agency Cullerton’s, which is handling the sale, says: “Whittingehame House is one of the finest of its kind, a truly special mansion house that is redolent with history. This, the principal apartment, has period elegance, grandeur and stately detail, yet it is also a warm and welcoming home – and has few of the overheads associated with a house of this nature.

“If it were the whole house, it might be too much, but this is a manageable size with the added benefit of private grounds.”

For those with budgets under £1m, Cullerton’s has just launched the garden flat at Whittingehame House onto the market, while Knight Frank is currently handling the sale of a first-floor apartment at the property.

Mark says of the Balfour: “It is very much lived in and enjoyed as a family home, but also lends itself very much to entertaining.

“It is such a unique house. The cornicing on the ceiling in the dining room is exquisite, and it has so many beautiful features in every room.

The Balfour, Whittingehame House, East Lothian. Image: Krzysztof Wrzos

“My client has Italian roots and because of that the outdoor temple space feels Italianate with its pillared cloisters. But it is used in a very modern way with an outdoor kitchen and a fantastic view.”

Mark predicts that the apartment will sell to a buyer from elsewhere in the UK or abroad, who may well acquire it as a second home. “It will definitely appeal to golfers, because of its location.

“I’ve never seen anything like it and although in the past I have sold more expensive houses, I’m not sure I’ve sold anything more spectacular.”

The Balfour, Whittingehame House, East Lothian, is priced at o/o £2.4m.

For more information, contact Cullertons on 0131-225 5007.

Prestige property: Purchase a prime portion of East Lothian history