Arabella Spencer-Churchill, granddaughter of Sir Winston Churchill has died at her home in Somerset, her husband confirmed.
Mrs Spencer-Churchill co-founded the Glastonbury Festival
Mrs Spencer-Churchill, 58, founder of the Children's World Charity, and heavily involved in the Glastonbury Festival, died after a short illness.
Born on October 31 1949, she was the daughter of Major Randolph Frederick Edward Churchill and June Osborne.
She died at St. Edmund's Cottages, Bove Town, Glastonbury.
She married James Barton in August 1972 and then renowned juggler Ian 'Haggis' McLeod 16 years later.
As well as being a director of the Children's World Charity, Mrs Spencer-Churchill was Governor of the Avalon Special School.
'Grief and sadness'
Paying tribute to his late wife Mr McLeod, 44, said: "My loss is everywhere. She was to my mind one of the few people I would lay down my life for."
Michael Eavis, who runs the Glastonbury music festival spoke of his "grief and sadness" at the news of her death.
"Her energy, vitality, and great sense of morality and social responsibility have given her a place in our festival history second to none," he said in a statement.
"May her place in the great eternity be always peaceful, and perhaps the mysteries of the heavens will accommodate her spirit forever."
Mrs Spencer-Churchill leaves one son, Jake Barton, 34, from her first marriage, and one daughter Jessica, 19, from her marriage to Mr McLeod.
She is believed to have been suffering from pancreatic cancer. The funeral is to be held in Yeovil on Christmas Eve.