Lady Lucan, whose husband vanished more than 40 years ago in a murder mystery that still piques lurid fascination and excites conspiracy theorists, has been found dead at home aged 80.

Veronica, the Dowager Countess of Lucan, was the only known witness to the terrible events that led to the murder of her children’s nanny, Sandra Rivett, 29, in 1974 at the family home in Belgravia, central London.



With her death, described by police as “unexplained” but not believed to be suspicious, the mystery will endure.



The countess ferociously maintained that Rivett was bludgeoned to death by her estranged husband, John Bingham, the seventh Earl of Lucan, who in the dimly lit basement mistook the nanny for his wife.



She always contended that she disturbed the aristocratic professional gambler during the fatal assault and he hit her four times with a length of bandaged metal piping before she managed to escape and raise the alarm at a local pub, the Plumbers Arms.



The head barman at the Plumbers Arms, Derrick Whitehouse, told a newspaper reporter at the time that Lady Lucan had staggered in and said: “I think my neck has been broken. He tried to strangle me.” He said she was in “just a delirious state” and had “various head wounds” that were “quite severe”.

Lucan vanished after the murder, his borrowed car found abandoned and blood-spattered, with a section of bandaged lead piping in the boot, at the cross-Channel port of Newhaven, East Sussex.



En-route to his unproven destiny, Lucan stopped off to visit friends in a Sussex village, telling them he had stumbled on an attacker hitting his wife, who then accused him of hiring hitmen to kill her, and that he was going to “lie doggo” for a while.



John Richard Bingham, Earl of Lucan, and Veronica Duncan after their marriage in 1963. Photograph: Douglas Miller/Keystone/Getty Images

An inquest later determined Lucan as Rivett’s murderer. He was never convicted in a criminal court. He was reportedly sighted in Australia, Ireland, South Africa and New Zealand. One claim had him fleeing to India and living life as a hippy called “Jungle Barry”. He was officially declared dead by the high court in 1999.

On Tuesday, Lady Lucan was found unresponsive at her Eaton Row mews cottage in Belgravia by police who had forced entry to the property after she was reported missing. Although the Metropolitan police are awaiting formal identification, a spokesman said: “We are confident that the deceased is Lady Lucan.”



Estranged from her three children, Frances, 52, Camilla, 46, and George, 50, a merchant banker and now the eighth Lord Lucan after his father’s death certificate was issued last year, she lived alone in the house where her husband had been staying a short distance from the former family home and scene of the murder.



George Bingham told the Daily Mail: “She passed away yesterday at home, alone and apparently peacefully. Police were alerted by a companion to a three-day absence and made entry today.” The paper said she was reported missing by a friend after she failed to appear in Green Park, where she walked every day at the same time.

Lady Lucan’s family said in a statement: “Veronica’s children and her sisters are deeply saddened by the news and circumstances of her death. Although Veronica severed relations with her family in the 1980s, and continued to decline contact with them right up until her death, all of them remember her lovingly and with admiration.

“She had a sharp mind, and when she spoke it, she did so eloquently. She was courageous and, at times, outrageous, with a mischievous sense of humour.

“She was, in her day, beautiful and throughout her life fragile and vulnerable, struggling as she did with mental infirmity. To us she was and is unforgettable.”

This year, Lady Lucan gave a television interview in which she said she believed her husband had jumped off a cross-Channel ferry, “in the way of the propellers so that his remains wouldn’t be found – I think quite brave”.



During the ITV programme, Lord Lucan: My Husband, The Truth, she spoke of her depression and her husband’s violent nature after their marriage in 1963. Describing how he would beat her with a cane to get the “mad ideas out of your head”, she said: “He could have hit me harder. They were measured blows. He must have got pleasure out of it because he had intercourse [with me] afterwards”.

Of her estrangement from her children, she told the interviewer, Michael Waldman: “It’s not my fault that I lost my family … it will always be a mystery to me.”

Waldman told the Radio Times: “She is, I think, genuinely perplexed as to how it all went wrong, but equally she is not bitter and twisted about it and is getting on with her life. You can take the view that she is selfish, or self-preserving.”