The fashion icon Isabella Blow ended her life by drinking the deadly weedkiller Paraquat, a coroner revealed yesterday.

Mrs Blow collapsed at her country home in Gloucestershire after telling weekend house guests, including the royal milliner Philip Treacy, whose hats she helped to make famous, that she was going shopping. She died in hospital on Monday at the age of 48.

Her husband, Detmar Blow, had told The Times that his wife had died of cancer — she had recently had ovarian cancer diagnosed.

But at the opening of her inquest yesterday, the deputy Gloucestershire coroner, David Dooley, said that tests on her body had tested positive for Paraquat.

Further toxicological tests are to be undertaken before a full inquest is held in October.

He said: “Mrs Blow had been taken to hospital on May 5, having been found in a poorly state by her sister. In hospital she told doctors that she had taken Paraquat and tests proved positive for this liquid.

“The initial cause of death was given by the pathologist, Professor Neil Shepherd, as death from the effects of a drug overdose. I have queried this with the professor and he says that is the right way of describing the pharmacological effect of any chemical on the body.”

Mr Dooley was opening the inquest and heard evidence of identification and post-mortem examination findings before adjourning until October 24.

Terry Onions, the coroner’s officer, told the hearing that the body of Mrs Blow was identified formally by Julian Patrick Jones, a neighbour and friend for the past 12 years. Mrs Blow had made at least two suicide attempts in the past, once by throwing herself from the Hammersmith flyover, which left her with serious leg injuries.

On the weekend of her death she was hosting a small party at her Cotswolds mansion.

Mrs Blow was as famous for her colourful life as her passion for hats and blood-red lipstick. She was a stylist who was once described as one of the 20 most influential people in fashion.

She was the granddaughter of Sir Jock Delves Broughton, who had been tried and acquitted for the murder of the 22nd Earl of Erroll in Kenya in 1941.

He later returned to Britain and committed suicide by taking an overdose. The story was made into the 1988 film White Mischief, starring Greta Scacchi and Charles Dance.

According to an author, tapes have been uncovered suggesting that Delves Broughton did shoot the earl. Recordings given to Christine Nicholls imply that he killed him — because the earl had had an affair with his wife, Diana — before establishing a fake alibi and disposing of the gun.

Mrs Blow married her husband, a barrister, in 1989 after a whirlwind romance. His father also committed suicide by drinking Paraquat.

At the age of 4, Mrs Blow witnessed the drowning of her two-year-old brother, John, in the family swimming pool.

She worked as a style editor and fashion director for, among others, Vogue, Tatler and The Sunday Times. She was renowned as a talent spotter and helped to launch the careers of Mr Treacy, Alexander McQueen and Julien Macdonald.

Her funeral will be held on Tuesday in Gloucester Cathedral, where she married.

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