The grand-daughter of Sir Winston Churchill, Arabella Churchill was a glamorous debutante who very publicly dropped out of high society to run the first Glastonbury festival.

In 1971 she was invited to represent Britain at the Norfolk International Azalea Festival in Virginia, established in 1953 after Nato's Allied command was established there. Each year a Nato country is honoured, and invited to send an “Azalea” queen as its ambassador. Churchill refused to go, instead writing a letter to Rolling Stone magazine, explaining that she believed in peace and love and was horrified by the war in Vietnam. When the magazine published Churchill's letter, it caused a sensation.

The paparazzi pursued Churchill through London; her family berated her: “My brother rang up absolutely furious with me,” she recalled. “My mother was saying ‘Darling, can't I just say you've had a nervous breakdown?' The whole thing was a nightmare. I felt I had let the family down. I felt I wanted to be a hippy. I felt I was left wing. I felt I didn't want to be like the rest of my family.”

Tiring of the attention, Churchill fled to Glastonbury where her friend Andrew Kerr had decided to put on a “free event” in the Vale of Avalon to mark the Solstice. Kerr, a hippy enamoured of the Arthurian legends connected with the area, had rented Worthy Farm near Pilton in Somerset.

The first official festival was utter chaos. Churchill, who had led a sheltered life, was initially shocked by the sight of couples “being free” with their bodies and drugs. She returned to London where in the mid-1970s she ran a restaurant for squatters in a house in Little Venice.

Eight years later she returned to organise a second festival with Kerr. The tickets cost £5 and the main act was Peter Gabriel. It ended in massive debt. But then the owner of Worthy Farm, Michael Eavis, took on the organisation and it began to run smoothly, a radical counter-cultural event, but thenceforth minus the original chaos.

In 1979 Churchill stayed put, eventually taking charge of the festival's theatre and circus fields, organising the small army of jugglers, sword-swallowers, contortionists, comedians, actors and dancers who perform each August. She regretted the increasing commercialisation of Glastonbury but said it had retained its charm — though fierce criticism had been sparked by tighter security measures in the 1990s.

Faced with an extra half million gatecrashers, Eavis had employed the Mean Fiddler organisation to tighten up security. In came ticketing systems, security guards and commercialisation, and out, claimed critics, went the hippies, the crusties and the original “spirit of Glastonbury”. A manifesto issued in 1971 defined the festival's aims as : “the conservation of our natural resources; a respect for nature and life; and a spiritual awakening”. Eavis claimed this original charism had not been lost, saying “We have to fight tooth and nail to hang on to the core values of the thing. Arabella is one of those who are essential to doing that.”

Arabella Churchill was born in 1949, the daughter of Winston Churchill's son, Randolph, and his second wife, June Osborne. Her grandfather died when she was 15, and he 91, but they had a close bond. She recalled watching a film about his leadership with an elderly Churchill during which he would grip her hand and mutter ferociously “Bloody Nazis” whenever Hitler's face appeared on the screen.

Though “immensely proud” of her grandfather, Churchill felt she was “no good at being a Churchill”, confessing: “People never saw me for me. It doesn't do a lot for your confidence.”

In this lay the seeds of her future rebellion, although at first she appeared on track for a conventional debutante future. She was voted “Deb of the Year” in 1967, and after working for London Weekend Television engaged in PR work for Lepra, the British Leprosy Relief Association. She travelled to Zambia and Tanzania for Lepra, giving talks on the experience when she returned.

It seemed only a question of time before marriage to a suitably grand suitor, was on the cards. “My father would say: ‘Damn, there goes the last duke getting engaged!'. It was a joke, but it wasn't a joke,” Churchill later recalled.

Instead, in 1972, she married John Barton, a teacher. A year later they had a son Nicholas (known as Jake) who has just been sentenced by an Australian court to three years in jail after being convicted of drug offences. They moved to Wales to a sheep farm but by 1975 the marriage was over. Churchill returned to London and charity work before going back in 1979 to Glastonbury.

Strong-willed and with a commanding presence, Churchill took responsibility for overseeing the 1,500 circus and theatre performers. In 1982, encouraged by the delighted expressions she witnessed on the face of children at the festival watching plays and jugglers, Churchill founded the Children's World Charity to bring performance arts to special needs schools. She raised funds to pay performers to work with special needs children to improve their communication skills and confidence.

Now the charity tours mainstream and special needs schools here and abroad. In January Churchill went to Aceh, to help tsunami survivors, with her second husband, Haggis McLeod, a professional juggler. “I know it sounds silly but just going in and doing things with them, making badges and Haggis juggling, really cheered people up.” she said.

Churchill attributed her passion for work to an inability to come to terms with her family background, explaining “It's why I have worked so hard . . . Glastonbury is a huge challenge every year. When you think that it's run by old duffers like Michael and me, the fact that so many people want to be there is very flattering. So actually, you know, I don't think I have let the family down at all, have I?”

She is survived by her husband, by their daughter and by the son of her first marriage.

Arabella Churchill, festival and charity organiser, was born on October 30, 1949. She died of pancreatic cancer on December 20, 2007, aged 58