They can be heroes - but just for one day

Children singing pop classics? Simon Price attends rehearsals for an extraordinary revival at David Bowie's Meltdown festival

Choir practice will have to wait. It's been a noisy morning at St Jude's Primary School in London's Herne Hill, perched between leafy Dulwich on one side, and the inner city vibrancy of Railton Road – the "front line" of Brixton – on the other.

To grown-up eyes, the England-Nigeria game may have been a 0-0 bore draw, but you'd never guess it from the riotous chanting of "Eng-land" (or, in some cases, "Nigeria!") in front of the big screen at the school gymnasium. The match strayed 15 minutes into class time, but Deidre Skinner, the Australian class teacher, reckoned that "for the sake of 15 minutes, it would be mean not to", and the infants' lungs, at least, would be warmed up. St Jude's is 95 per cent Afro-Caribbean. So why is the school choir about to recreate an obscure recording made a quarter of a century ago by white children in Canada? The answer involves one of the most peculiar musical success stories of recent times.

In 1971, a 24-year-old Vancouver musician and self-confessed "guitar-strumming hippie" named Hans Fenger was scraping a living by giving guitar lessons and gigging in rock clubs. When he learnt that his girlfriend was pregnant, he decided it was time to get a proper job, and became a teacher. In 1974, he was assigned to teach at three schools in the rural area of Langley, British Columbia, a Canadian equivalent of the Bible Belt, where some children literally rode to classes on horseback.

Inspired by the teaching theories of Carl Orff and the simple-but-monumental arrangements of Phil Spector, he began teaching the children, aged between nine and 12, to play pop hits of the recent past (predominantly by The Beatles, Beach Boys and David Bowie, with an approach which valued enthusiasm over perfection: "I don't feel that getting it right is getting it right," he explains now. "I used to say 'If you can't sing, sing louder!'")

Surveying his long hair, gypsy scarves and George Harrison moustache, the conservative elders didn't quite understand Fenger or his techniques, but from the children's responses, they knew he had to be doing something right. In 1976, armed with a two-track Revox tape machine and a ramshackle assortment of battered instruments, he convened the pupils of Glenwood, Lochiel, and South Carvolth Elementary into a school gymnasium to record their performances for posterity. A year later, he did the same at Wix-Brown Elementary.

At the time, only 300 vinyl copies were pressed for the participants and their families, and that's where the story ended. Until June 2000, when a copy of the children's sinister, spooky rendition of "Space Oddity" fell into the hands of Irwin Chusid, a New York-based author, DJ, and collector of what he terms "outsider music". Enchanted by what he heard, Chusid hunted down the full recordings, tracked down Hans Fenger, now back in Vancouver and still teaching, and set about persuading his friends at Basta Music, a Dutch Record label, to release the whole thing on CD.

By last December, the album, titled Innocence & Despair and credited to The Langley Schools Music Project, had sold 50,000 copies in the US alone, largely via word-of-mouth, much to Fenger's surprise and delight. It has since been released in Japan, France, Canada and the UK and is now something of a worldwide cult.

One fan of the album in general, and "Space Oddity" in particular, is David Bowie himself, who was moved to say: "The backing arrangement is astounding. Coupled with the earnest if lugubrious vocal performance, you have a piece of art that I couldn't have conceived of, even with half of Colombia's finest export products in me." When Bowie was invited to curate this year's Meltdown festival, he commissioned a conductor named Laka D to arrange a re-enactment of the whole project, entitled Langley Schools Revisited. Which is where St Jude's (and six other Lambeth schools) come in.

I ask Fenger whether he can hear what people like Bowie – and the rest of us – hear in the recordings, namely their haunting quality. He says that effect was unintentional, but that "good music tends to sell itself. Although people have heard 'Good Vibrations' a million times, I think hearing this version brings back the feeling they had the first time they ever heard it." Part of the appeal of the recordings, which were almost all done in one take, is down to the lo-fi majesty of the arrangements, which recalls Phil Spector (imagine the Wall Of Sound made of Lego bricks). The difference, of course, is that while Spector believed he was making "little symphonies for the kids", Hans Fenger went one step further: he created little symphonies by the kids. "What I loved about Spector," says Fenger, "was that he'd take a small idea, like 'Be My Baby', and make it sound Wagnerian. He'd have a hundred pianos and one castanet, and the castanet would come out the loudest.

"We had the same thing: the bell instruments would be the closest to the mic, and they'd come out the loudest. We didn't have a studio, but we had a big empty gym, with a whole load of reverb." The real beauty, however, lies in the uncanny, beyond-their-years evocativeness of the singers' voices. There is an incredible power in hearing the voices of children who, one assumes, know nothing of love, fear, loneliness and loss singing about those subjects.

"Children are people," Fenger affirms, "with the same emotions as the rest of us. They know nothing of the way adults feel love, fear, loneliness and loss, but an eight-year-old whose parents are divorced knows loneliness. An eight-year-old who's alone in a room with someone picking on them knows fear." The choice of songs was crucial to Fenger's approach.

For me, the album's most moving moment is nine-year-old Joy Jackson's solo performance of "The Long and Winding Road". For many others, it's The Eagles' "Desperado", by Sheila Behman. "Joy sang it in a way that even Paul McCartney couldn't," says Fenger. "When we hear the original, we think of the Beatles at that time – it's so sad they were breaking up, and so on. With Joy, we hear the song in a purer way. And the same with Sheila. She knew none of the literary references – films like Shane, the lone cowboy riding into the sunset, and so on ..." To tap into their emotional reservoirs, Fenger sometimes had to think laterally. "For 'Space Oddity', they didn't know about the drug connotations – the more frightening and heavy it got, the more they loved it, they just got off on the sheer terror! And when we were doing 'Mandy', I asked them to imagine that it was about a dog, and they completely understood it."

Down at St Jude's, this is the task of Matthew Sharp, an enthusiastic young cellist, opera singer and actor who has been hired to fulfil the Fenger role, at short notice (rehearsals began as recently as half-term). The choir sit cross-legged and straight backed, but otherwise it's all very informal: they call him "Matthew", not "Mr Sharp". Today, he's teaching them Herman's Hermits' "I'm Into Something Good". Singling out the line "Don't know if we'll fall in love", he asks them to imagine the anxiety and hope contained in it. "Do you think he wants to fall in love?" he asks. "Yesss!" they reply.

Given that the material was written, in many cases, before even their parents were born, how are they responding? "They really go for the Beach Boys stuff, like 'I Get Around', because of its immediacy. Some of them like 'Space Oddity' because it's in the film Thunderpants, but others get a bit perplexed by it." Ten-year-old Funmi is definitely perplexed. "It's too low," she complains, "and it has too many words." She is, however, excited that she might be performing for its creator at the South Bank. Andre, aged nine, is laid back, dry and funny. A fan of R&B and Garage, he'd prefer to be doing Usher and Eminem, but can't imagine it ever happening. "It's all classics, he says, pulling a face.

Such dissent receives short shrift in the classroom. After half an hour, a couple of the younger kids are starting to nod off. Deidre suggests they should try another song, Neil Diamond's "Sweet Caroline", and there are a couple of grumbles. "You can go back and do Maths if you prefer!"

When Fenger's own alumni had a reunion earlier this year, he was thrilled to find that so many of them had gone on to pursue careers in music. "It was amazing, extremely emotionally moving. They started singing, and it was as though they were nine years old again, as if nothing had happened in between. Many of them had gone on to careers as singers, DJs, recording engineers, so the idea of doing something in music had stayed with them. Which was the whole point." Exerting his influence over the Lambeth pupils, however, has proven unrealistic. "It's hard to teach from 5,000 miles. I've spoken to the organisers a bit, and exchanged emails. I just said 'Have fun with it.'" Amen to that.

The Langley Schools Revisited concert: Ballroom Floor, Royal Festival Hall, London SE1 (020 7960 4242), Friday at 5.30pm. Admission is free