Upon the death of his older brother in 1910 when he became the 6th Earl Spencer, he moved to the family seat Athorp House, where Diana grew up and is buried.

Dallington Hall was given to the council to use during the war.

The Grade II Listed house was sold in 1980 and converted into apartments.

This five-bedroom property, on the market for £995,000, comprises a major portion of the townhouse.

It was built in 1720 for Sir Joseph Jekyll, a prominent barrister, judge and Master of the Rolls.

The house has a striking front door and a magnificent two-storey listed Georgian oak staircase.

It has 4,663 square feet of accommodation over three floors.

The wine cellar is now a vaulted games room on the lower ground floor and there is also a sauna.

On the ground floor, there is a drawing room, dining room, kitchen and sitting room, as well as an impressive hall.

Five bedrooms and two bathrooms complete the upstairs floor.

Outside is a sunny south-facing terrace, a mews courtyard and a garden complete with a lawn, an ornamental pond and mature trees.

Nick Pattison, from Jackson-Stops, which is selling the property, said: "Dallington Hall is exceptionally beautiful and something of a lifestyle property.

"It occupies the largest part of the mansion block and offers a rare opportunity to be the custodian of a very important building.

"One of the property's most striking attributes is the wonderful hallway with the separately listed Georgian staircase."

He went on to say the Spencer family's ancestral home for more than 500 years, Althorp House is nearby.

Nick added: "Dallington Hall once belonged to Diana's great uncle, the Rt Hon Charles Robert Spencer.

"He was a member of the Conservative Party and represented Northamptonshire North in Parliament in the 1880s.

"He would regularly wine and dine party members in the wine cellar, which is now the games room.

"When his brother passed away he became the 6th Earl Spencer and moved to Althorp.

"He gave Dallington Hall to the council to serve as a convalescent and respite home for wounded soldiers during the Second World War.

"It's certainly a property that captures the imagination."