While the camera was rolling

Cocksucker Blues. I'm still waiting to get my hands on a copy, or see a screening somewhere. While the camera was rolling:
Pop: Robert Frank's 1972 film about the Stones was supposed to help put the scandal of Altamont behind them. But the wild scenes he captured on tour only added to the band's notoriety.

For a film with such limited circulation, the cast on the screen is mightily impressive. Grinning, slightly unsure of himself, on assignment for Rolling Stone magazine, there's Truman Capote. Accompanying him, brandishing the cassette recorder that is now his constant companion, Andy Warhol. And, of course, there's the star of the show. Just in case you couldn't guess this was him, he's wearing a sequinned body suit. This, of course, is Mick Jagger.

The cast list - essentially comprising the great and the good of early 1970s American celebrity - doesn't diminish in its capacity to impress. Noticeably dishevelled, there's Terry Southern, noted screenwriter of Dr Strangelove. There's Jackie Kennedy's sister, Princess Lee Radziwill, another member of the Capote party. But even in this esteemed company, it's perhaps the film itself that has a more notorious name than anyone present in its backstage scenes. Shot by the American photographer Robert Frank and his young colleague Danny Seymour, this - 16mm, in shaky black and white - is a film called Cocksucker Blues.

In the 32 years since it was made, Cocksucker Blues has come to occupy a unique cultural place. In Don DeLillo's Underworld, a character speaks of loving "the washed blue light of the film ... corruptive and ruinous, a beautiful tunnel blue". In rock legend, it occupies a place as a record of the kind of bacchanalian excess - nodding out backstage, oral sex on private jets - that one has come to imagine the rock star demands as his right. In troublesome fact, it has continued to be an object of contention between Robert Frank and its subjects, the Rolling Stones. Even today, with a huge show of Frank's photography and a programme of his film work about to open at Tate Modern, the film is subject to stringent (and private) exhibition restrictions.

It was, of course, not meant to be this way. Having used one of his photographs for the cover of their Exile On Main Street album, and been impressed by his landmark 1958 monograph The Americans, in 1972 the Stones commissioned the 48-year-old photographer to make a film of their triumphant return to concert performance in the United States. Three years previously, the Maysles brothers documentary team had witnessed the tragic denouement at Altamont Speedway of their concert ambitions for 1969. This time, things were going to be different: new record label (their own Rolling Stones records), new attitude (concerts running like clockwork, not turning into bloodbaths), new Rolling Stones. Celebrity journalists would record the band's progress. Meanwhile, a film of proceedings would satisfy both the desire for a record of the concerts, and Mick Jagger's film-making pretensions.

"One of the rules when making the movie was that none of the people in the Rolling Stones could say no," explains documentary director Paul Justman, then an editor on the film. "If they said no, then Robert put the camera down and he left. There wouldn't be any anger or anything. It would be like, 'OK, you guys have given up and said no to me. Get someone else'."

It was this policy, above all, which led to the unique quality and content of Cocksucker Blues. Certainly, the film did contain footage of the Rolling Stones playing some of their finest rock'n'roll, but this was shot by another crew. What Frank concentrated on was the periods of time between these shows: periods of time-killing, crotch-scratching and, frankly, boredom that can evidently also accompany the rock'n'roll life. There are notorious scenes - Keith Richards dumping a TV out of a window; a choreographed sexual encounter on board the Stones' jet, the so-called "lapping tongue" - but perhaps more representative of the content are two others. One where Keith attempts to order some fruit from room service. And another, where Mick Jagger films himself preparing, not to put too fine a point on it, to masturbate.

"Technically," says Susan Steinberg, who edited the film, "it was a complete mess. There was a light leak in the [camera] magazine. Most people who saw this happening would have got the light leak fixed or got a new magazine, but Robert didn't. He didn't believe in that, and it's that attitude that's very prevalent in the film. It's down and dirty."

An anecdote recorded by Terry Southern, meanwhile, recounts Frank's attempt to explain to Keith Richards exactly what it was he was after in the film.

"It's vérité," he said.

"Never mind vérité," the guitarist reportedly replied, "I want poetry."

This, after a fashion, is what he got. Assembled over the course of the next two years in Frank's loft on the Bowery, Cocksucker Blues slowly began to take shape. Bob Dylan would pop in to look at what they'd done. The team screened their material for interested celebrity parties at John Lennon's editing suite. Meanwhile, every two weeks, Mick Jagger would drop by to relish the relative anonymity afforded by the Lower East Side locale, eat Chinese food, and check on the progress of what was becoming a film with its own impressively perverse logic.

Not everyone was so impressed with Frank's freewheeling pursuit of vérité. George Griffin, an animator roped in to provide the film's graffiti-style titles, remembers the time with a certain frustration.

"After having sprayed numerous titles, each increasingly more rough, spontaneous and 'authentic'," he explains, "Robert shot them while walking around, swooping, and sort of discovering them within the rubble of the roof. Only to discover, at dusk, that he had forgotten to load film into the camera."

"It wasn't commercial," concludes Paul Justman. "It wasn't product. Robert doesn't make product. Whether it was good art or bad art - that's what he meant."

Though supportive of the project as individuals, as an organisation the Rolling Stones were perhaps always going to have problems with Cocksucker Blues. Containing scenes where the band are surrounded by heavy drug use (in the credits, Danny Seymour is billed as "Junkie Soundman"), as well as heavily implying their own drug use, whatever the film was - staged documentary? Fiction, as a disclaimer in the titles implied? - it didn't fulfil a helpful function for a rock'n'roll band aiming to cross international borders as part of their day-to-day working life. Finishing the film completely being an expensive process, the Stones instead paid for a rough mix and a print, and then the cutting room was shut down. In the place of Cocksucker Blues, to little fanfare, they released the anodyne concert film Ladies And Gentlemen, The Rolling Stones.

The trail of the movie went cold until several years later, when Susan Steinberg got a call from Mick Jagger. With Frank's permission, the pair were to clean up parts of the movie, with a view to a release. Keith Richards was then busted for drug possession in Toronto. The plan was shelved.

Since then, the film has been left to work its way into the culture as a contraband artefact. Available to view only at restricted screenings - one of the provisos being that Frank must be present; the film must be viewed in the context of his, and not the Stones', oeuvre - it's otherwise a famous rock bootleg item, though one with a weighty pathos attached. While the film was being completed both Frank's daughter Andrea and his colleague Danny Seymour died, events the photographer would work through in subsequent films.

Filled with moments of beauty and insight, meanwhile, Cocksucker Blues is left to add new depth to what would otherwise simply be a film about an excessive rock'n'roll junket. "It's such a time capsule of what life was like behind the scenes in 1972," says Susan Steinberg. "I've always wanted to get it released and seen. What was controversial at the time is now history."