The Marquess of Ailesbury, who formerly owned Savernake Forest near Marlborough, has died unexpectedly after falling from a first-floor window.

Michael Sydney Cedric Brudenell-Bruce, the Marquess of Ailesbury, 98, was at his London home in Shepherd's Bush in the evening on Sunday, May 12 when he is thought to have fallen out of a window.

His son, David Brudenell-Bruce the Earl of Cardigan, told the Gazette and Herald his father had been suffering from dementia in the months leading up to his death.

He said Teresa Marshall Di Paoli, who was the Marquess's partner of 37 years, discovered his body when she went to find him in the garden.

According to the Earl, Teresa had looked up at the bedroom window and saw it was open. He said the window of the house is not used and is never usually opened.

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The Wiltshire Gazette and Herald: The Marquess of Ailesbury has died unexpectedly aged 98.The Marquess of Ailesbury has died unexpectedly aged 98. (Image: Shutterstock)

Hammersmith CID remained at the scene on Abdale Road in Shepherd's Bush for six hours.

Despite national media claiming that the Marquess fell while letting a cat out of the window, the Earl said there was no evidence that the cat was involved in the incident and the death is being treated by police as unexplained.

"Contrary to what some people might have seen in the national papers, there is zero evidence that any cat was involved at any point. I have been told that the enquiries made by Hammersmith CID are continuing," the Earl said.

The Earl of Cardigan and his son Viscount Savernake are currently the owners of Savernake Forest, which is Britain's only privately owned forest.

The 4500-acre forest estate has been handed down from generation to generation within the family since 1067 and was passed on to the Earl in 1980 after his father, a stockbroker, decided he had no interest in rural affairs.

Despite being described as a reserved and rather unemotional man, The Marquess of Ailesbury enjoyed time with his family and took an interest in gambling and horseracing.

"I took my 10-year-old daughter up to London the weekend before last and we had a lovely tea party with him and he was in excellent spirits," said the Earl of Cardigan.

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"He kissed her fondly on both cheeks and she was thrilled."

LBC have reported that Met Police confirmed they attended the address at just after 8pm on Sunday and the London Ambulance Service attended.

"The death is unexpected but not being treated suspicious," a spokesperson told LBC.

An inquest is expected to be carried out into the Marquess' death later this summer, but no date has been confirmed.

Until then, the family has asked that members of the public refrain from speculation and treat the death as unexplained.