Andrew Kerr, who has died at the age of 80, was one of the founders of the Glastonbury festival (or "fair", as it was named in 1971). It was after attending the somewhat shambolic Isle of Wight festival in 1970 that he declared: "We've got to have a proper festival," and approached the Somerset dairy farmer Michael Eavis, who was already staging a small festival near Glastonbury.
"What I was asking seemed even to me a bit loopy," admitted Kerr later. For the summer solstice of the following year, he planned a festival in the vale of Avalon; the event would be free, making it "a giving event which sought a spiritual awakening and a demonstration against greed". It would be funded largely by Kerr (he ended up selling his grandfather's 60-year-old 12-bore shotguns) and by Sir Winston Churchill's 22-year-old granddaughter, Arabella Churchill, who was Deb of the Year in 1967 before she revealed her inner hippy. Her brother, the MP Winston Churchill, considered Kerr to be "intolerably hip", a description that he delightedly took for the title of his fascinating if ragged memoirs (2011).
Perhaps surprisingly, Eavis agreed to let this "crowd of upper-crust hippies" rent Worthy Farm, in Pilton, Somerset, which conveniently turned out to be on the ley line between Glastonbury Abbey and Stonehenge. Bands playing on the stage, built in a pyramid shape that came to the designer in dreams, included Fairport Convention, Arthur Brown, David Bowie, Traffic and Hawkwind.
Kerr was a member of the hip upper-middle-class 1960s set fascinated by "earth mysteries", and Glastonbury, with its Arthurian legends, drew his crowd like a mythical magnet. Educated at Radley college, he was the walking symbol of the worlds of relaxed privilege and mysticism. Jan Roberts, whose late husband Tony was a fellow student of the "sacred geometry" of the landscape, recalls "the great hair and the very regal attitude".
For Kerr the two worlds often collided. Sitting stoned next to Princess Margaret at a dinner, he horrified fellow guests by explaining to her at some length and volume that Jesus was a "hybrid" from a planet named Heaven; it was said that she passed this intriguing theory on to the archbishop of York.
Born to Mark Kerr, a naval commander, and his wife, Mary, Andrew was a descendant of the third duke of Buccleuch, and was described by his eldest brother Frederick as "one of the two black sheep of the family". (Freddie admitted he was the other.) He grew up in Oxfordshire and Devon, and was considered charming and charismatic, although his four siblings irreverently referred to him as Ape.
He began his working life with a brief stint in advertising and a longer period at the AA as a receptionist. In 1957 a man he met in a Soho bar said: "Why don't you have my job?" Next morning Kerr found himself on a train to the Suffolk mansion of Randolph Churchill, father of Arabella, whom he met there for the first time. He was promptly hired, initially as a researcher on the biography of Sir Anthony Eden.
Despite being dyslexic and having only six School Certificates, the new employee became invaluable to the autocratic boss as a friend, fellow drinker, proofreader, personal assistant and the only person who could operate the boiler. He was working on the next project, a massive biography of Sir Winston, when Randolph died in June 1968. Devastated, Kerr left soon afterwards and became a researcher at Yorkshire TV.
After the end of the first five-day Glastonbury fair, Kerr and his partner, Jytte Piggott, left for Scoraig, a remote Scottish croft, where they had two children. When the relationship foundered, a desolate Kerr returned south. He became a worker for the Divine Light Mission of Guru Maharaj Ji, who had given the fair the benefit of his wisdom, addressing it at the age of 14.
Kerr built dry-stone walls. He crewed yachts. He went to Hollywood to write a script. He set up The Whole Earth Show in Dorset in 1992. Meanwhile the Glastonbury fixture had taken on a life of its own, as people turned up over the midsummer period every year for impromptu cavortings.
In 1981 Eavis took over the renamed Glastonbury festival and Kerr came "home" on this occasion and in subsequent years, helping to celebrate the 40th anniversary in 2011 with performers from the original 1971 event. He was still visiting the site until a few days before his death.
He is survived by his children, Martha and Jonah.
• Andrew Philip Kerr, born 29 November 1933; died 6 October 2014
