The stepfather of the Earl of Pembroke has been found dead on the grounds of one of Britain’s most famous country houses.

Stuart Wyndham Murray Threipland was found with a gunshot wound to the head, near to his car which was parked at Wilton House, a 14,000-acre Palladian estate close to Salisbury, in Wiltshire.

Mr Threipland’s death came on the same day his estate and 13-bedroom castle at Dunbeath, in Scotland, had been listed for sale by property agents Savills for £25million.

According to records from Companies House, Mr Threipland was a director of 15 firms until he resigned from each one on June 12, the day of his death.

Police are currently not treating the death as suspicious, and said the 76-year-old would have died instantly. 

Stuart Wyndham Murray Threipland was found with a gunshot wound to the head

Wilton House – where his body was found – is a 14,000-acre Palladian estate close to Salisbury, in Wiltshire 

Mr Threipland’s death came on the same day his estate and 13-bedroom castle at Dunbeath, in Scotland, had been listed for sale by property agents Savills for £25million 

A statement from Wiltshire Police said: ‘Officers were called to an address in Wilton at 1.10pm on June 12 following a report of a sudden death of a man in his 70s.

‘There are not believed to be any suspicious circumstances and a file will be prepared on behalf of HM Coroner for Wiltshire.’

In a statement, the family said: ‘Stuart Murray Threipland, known to many as Tertius, sadly died on June 12 in Wilton, and he will be hugely missed by all his family.’

His sprawling castle is being described as a ‘magnificent A-listed castle’ with a dramatic coastal estate ‘of uncompromising quality’ which extends out to 28,500 acres of land.

The castle contains 13 bedrooms, nine bathrooms and three reception rooms. It also features a pair of walled gardens which are located within a designed landscape, a grouse moor and a deer forest. It also boasts 12.5 miles of double bank fishing.

Mr Threipland had been married twice, first to Belinda Mary Musker, the mother of his three children

Mr Threipland married Claire Rose Pelly after divorcing his first wife

Ms Pelly is seen at her wedding to the Earl of Pembroke at Holy Trinity on Brompton Road

An inquest at Salisbury, Wiltshere, was told on Thursday that Mr Threipland was found unresponsive lying close to a shotgun. A friend identified the body after police were called to the scene.

A post-mortem examination confirmed the cause of death was a gunshot wound to the head. Further tests were ordered and the inquest was adjourned to a date in August.

Mr Threipland had been married twice, first to Belinda Mary Musker, the mother of his three children, before marrying Claire Rose Pelly after divorcing his first wife.

Her son, William Herbert, the 18th Earl of Pembroke, inherited the mansion and its sprawling estate,  as well as a £115million fortune, when his father died of cancer in 2003.

It was until just May this year that Mr Threipland had served as chairman of machinery manufacturer Kitagawa Europe, who said he had an ‘unwavering commitment to excellence’.

According to records from Companies House, Mr Threipland was a director of 15 firms until he resigned from each one on June 12, the day of he died

Dunbeath Castle sits on the coast of Caithness, Sutherland and would offer any potential buyer a home that wouldn’t look out of place in a fantasy novel

The property remodelled extensively in the 1860s which included radically transforming the grounds

The company’s statement read: ‘We will forever cherish his wisdom, mentorship and the genuine care he displayed towards others.’ 

Dunbeath had been owned by Mr Threipland and his wife since 1997, with the castle dating back to the 15th century. 

The property remodelled extensively in the 1860s which included radically transforming the grounds.

Savills described it as ‘a paradise of moorland, riverside and coastline; a place to relish the absolute personal remoteness and to create unforgettable childhood memories’.

The castle is located in Caithness, which is one of the country’s most remote counties and was visited often by the Queen Mother, who owned the Castle of Mey for half a century.