A party at the flat of a German aristocrat ended in tragedy last night when a man fell 60ft from a window of a Chelsea property.

The man, in his late thirties, was pronounced dead at hospital.

The incident happened at approximately 5.30 this morning.

Police sources told The Sun newspaper that a ‘gay sex party’ was taking place at the flat of Count Gottfried von Bismarck.

The 42-year-old aristocrat is the great-grandson of the 19th Century German chancellor Otto von Bismarck.

He was involved in a scandal 20 years ago when the daughter of Tory cabinet minister Paul Channon was found dead in Bismarck’s bed.

A spokesman for the Metropolitan Police said: “A man in his late 30s was taken to hospital where he was pronounced dead.

“The victim has not yet been identified, and the incident is being treated as suspicious. A 41-year-old man has been arrested and is in custody.”

The arrested man is alleged to have left the scene after the man fell.

The count was not arrested and no drugs were found at the flat.