Based on what appears slight raw material – three minutes of film shot at a party in Malmö, Sweden, in 1965 – Rolling Like a Stone is one of the more emotional music documentaries of recent years.

The party was no ordinary teenage wingding – guests included Mick Jagger, Keith Richards and Brian Jones, trying to escape the madness over the water in beat-crazed Copenhagen. For a few days the three key Stones stayed at the home of Ola Strom, the singer with local band the Gonks, and a neighbour had the foresight to do some filming. “For a moment,” says co-director Magnus Gertten, “all those people are at the centre of the world. You can see it in their eyes.”

The documentary, being shown in the Barbican’s Pop Maverick series, which I was asked to curate, is one of a current crop in which the bit players take centre-stage.

“For me, the documentary is about how hard it is to live in the present,” says Gertten, who discovered the footage existed while working for Swedish Radio in the Eighties. When he finally saw it, he had the idea of tracking down the people at the party to discover what became of them.

“Most have been talking about it all their lives, hanging on to that moment of magic.”

There’s the blonde beauty whom Brian Jones wanted to move in with, and Strom who has kept all his fan mail and still wears his fringe as if he’s about to burst into Mr Tambourine Man. One character who stands out is Tommy Hansson, singer with another local band the Namelosers, who supported the Stones at their Swedish shows. There’s little doubt about how much the Stones affected him: “It was a fantastic time, oh my God! And after this we played with the Who, Jimi Hendrix . . . round the clock there would be six or seven girls outside my door. We broke up, and it was back to normal life again. Terrible.”

Gertten says Hansson has never got over the Sixties. “Tommy still has a dream of putting a band together. He still wants to be a rocker, but we know it’s too late.” The Namelosers weren’t new to Gertten when he found the footage. “They had credibility, they had a name. The Namelosers were the Swedish underground’s Rolling Stones, only playing from 1964 to 1967, but they made some great garage rock records.”

The group broke up when it was time for military service – something no British band has had to fret about since 1960. Have they thought about playing together again? “No,” says Hansson sadly. “Our bass player passed away and the lead guitarist is not interested.”

Gertten’s film has had more luck, winning “best music documentary” at the Washington-based Silverdocs festival. “People say Rolling Like a Stone has a bit of Ingmar Bergman about it – I think that’s just because we’re Swedish.”

Hansson is now a pensioner and separated from his wife and children, but sees himself more as a minor rock legend than a Bergman character.

“I just want to say ‘keep rocking’ to Mick and Keith,” he chirps. “I hope they never forget that lovely week in Malmö.” For Tommy’s sake, you hope they didn’t forget it years ago.

Rolling Like a Stone, October 7th. Barbican, London EC2 (www.barbican.org.uk 020-7638 8891)

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