This is not a chronological plod through the festival’s evolution, so much as a thematic and story-driven exploration of the peaks and troughs, the agonies and the ecstasies, that have shaped its many eras. Balancing the driving forces of social conscience and hedonism, Glastonbury has always been both a world apart and a barometer of the state of the nation. Cameras take viewers backstage and deep into the archive to reveal the forces that have driven this alternative nation between utopia and dystopia, the Greatest Night Of Your Life and a Muddy Field In The Middle Of Nowhere.

Opening with Billie Eilish and Stormzy backstage in 2019, viewers are almost immediately plunged into the nuclear threat that drove Glastonbury’s alliance with CND in the early 1980s, before meeting Johnny Marr and Mike Joyce of The Smiths who share how their 1984 slot reconnected this hippie gathering with the musical zeitgeist.

The template of Glastonbury’s combination of social conscience and musical immediacy has been set. The film then journeys back in time to the first Glastonbury festivals – the inspirations of dairy farmer Max Yasgur’s Woodstock in 1969 and the nearby Bath Festival of Blues and Progressive Music down the road in Shepton Mallet in June 1970 – swiftly followed by Michael Eavis’ pastoral village fete in Pilton a couple of months later, which was intended to pay off the mortgage on Worthy Farm and trade upon the Utopian vibes of the mystic Vale of Avalon. Then it’s onto 1971’s free Glastonbury festival of liberty and lawlessness, as recalled by singer-songwriter Linda Lewis, who hung out with David Bowie and sang with Terry Reid that year.

Talking in the film, Michael Eavis says: “It’s an unusual model really that we’re running here but that’s why it works I think. Three million people want to come to this event, which is a huge number, because of what it offers them I suppose… isn’t that enough for me? Don’t you think so? I think that’s plenty, come on, for a chap that’s 86, 87… to be satisfied with my life, surely.”

The rollercoaster ride escalates as Glastonbury takes on Maggie Thatcher, embraces the travellers then eventually drives them off, while keeping the determined talents that will enrich the festival’s extracurricular offering at Lost Vagueness, Block9, Arcadia, Pangea, and Carhenge.

Dance culture, drugs, Britpop and Blair, Radiohead and rain, The Fence, Jay Z, the arrival of television and identity politics are woven into a tapestry told by the Eavis family, the event’s many curators, and the musicians – Thom Yorke, Florence Welch, Dua Lipa, The Levellers, Aswad, Orbital, Fatboy Slim, Linda Lewis, Noel Gallagher, Ed O’Brien, Chris Martin, and Stormzy all tell it like it is.

Throughout, unfolding events are orchestrated by a Greek chorus of apposite stage performances from the likes of Dave, Sinead O’Connor, Massive Attack and Arthur Lee & Love, which often float free from the year they were given to soundtrack the politics and the emotions of Glastonbury’s struggles with a wider Britain.

The film dramatizes the forces that have kept Glastonbury Festival moving forward despite the threats that have sought to destroy its magic. So much has changed in the 50 years and counting of the festival’s journey, yet so much has remained constant. At the heart of the film is an emerging portrait of dairy farmer and impresario Michael Eavis – who CND’s Bruce Kent describes as “a funny little man”, Cinemageddon’s Joe Rush as “an anarchist”, and Block9’s Gideon Berger as “fantastically open-minded” – and his daughter, Emily.

Glastonbury Festival began as Michael’s money-spinner and has morphed into a vast wonderland where he’s brave enough to enable all kinds of music and all manner of fun which don’t always sit easy, either with his personal taste or his Methodist conscience; while Emily now curates the diverse artist bookings and drives the festival’s progressive environmental approach.

Producer/Director: Francis Whately; Executive Producer: Mark Cooper for BBC Studios