The Marquis of Bristol has died at the age of 44, his agent said yesterday.

Lord Bristol, who was jailed twice for possession of drugs, died in his sleep and was found yesterday morning at his home, Little Horringer Hall on the Ickworth estate in Suffolk.

The agent, Mr Simon Pott, said Lord Bristol's half-brother, Lord Frederick Hervey, 19, who is studying at Edinburgh University, would become the 8th Marquis of Bristol.

Lord Bristol's drug addiction had cost his family an estimated #7m in less than 10 years, a court was told in 1993.

Mr Pott said that the marquis had been ill for a short time but his death had come as ''a great shock''. The agent said he believed he had been suffering from a flu-type illness.

''It is a great shock to all of us and a most unexpected thing to happen,'' he said.

Lord Bristol, who inherited Ickworth - a 4000-acre estate - from his late father Victor, gave the property to the National Trust in 1998 and moved into Little Horringer Hall, a five-bedroomed farmhouse.

Reports at the time said that he moved out for an undisclosed sum after selling the remaining 64 years of a 99-year lease on the east wing of Ickworth House.

In 1996, the Harrow-educated 7th Marquis sold many of his belongings for an estimated #2.5m. He also sold many of his family lordships at auction.

Three years previously, in December 1993, he was jailed for 10 months at Snaresbrook Crown Court in London for possession of heroin and cocaine.

In 1984, before he became a registered drug addict, he described heroin as ''evil'' and ''wicked'', and said: ''I've always been against narcotics and always will be.''

In 1988 he was arrested in Jersey and served nine months in prison after #1000 of cocaine was found on his private helicopter. In 1989 he was fined #3000 for offences relating to drug possession.

His 1993 trial heard how police had found drugs hidden among the Old Masters and Chippendale furniture in Ickworth House.

Cocaine had been stored in a gold Russian snuff box and a canister of Pledge furniture varnish had been adapted to hold a secret compartment in the bottom.

Earlier in 1993 the marquis was saved from prison when a judge allowed him to receive treatment. However, after just one month in a clinic he discharged himself and fled to the south of France.

He led a colourful life, courting publicity almost every step of the way. It was said that he once blasted the door off a fridge with a shotgun to get a bottle of champagne.

He inherited #4m when he was 21, in addition to a 57,000-acre Australian sheep station, four oil wells in Louisiana - and Ickworth.

The marquis emerged from a rehabilitation clinic in 1996 and denied press reports that he was dying of Aids.