They've just bagged the most hotly contested and coveted slot in the musical cosmos, but Basement Jaxx don't look too fussed about it. Felix Buxton, the bearded and bespectacled one with a strangled voice like newspaper being scrunched up, seems more interested in his scrambled eggs and smoked salmon than slipping into Kylie's size threes. "We're just playing an hour later than we were originally," he says nonchalantly, "which is good 'cos it'll be dark and the lights'll look better."
At this point his bandmate Simon Ratcliffe clearly realises that more enthusiasm is required, and rises to the occasion. "We are really excited about it," he says. Honest. After a while in their company, you believe them, too. Their lackadaisical manner is not to be confused with indifference: they are just blessed with monotone speaking voices that make the most thrilling news sound like a weather warning. After Buxton has polished off his breakfast and put down his knife and fork he makes up for the drawl with huge hand gestures.
When Kylie withdrew from the Sunday night headlining slot at Glastonbury last month after being diagnosed with breast cancer, the music press was abuzz with gossip about who would replace her. The smart money was on the Scissor Sisters, who, it was decided, could match Minogue on the feather boa front. Then last week came the announcement that Basement Jaxx would move up the bill.
To those who had never witnessed the Jaxx spectacle live, it was a surprise - but to those who had, it was clear Basement Jaxx would be the perfect replacement. Canny enough to realise that watching two middle-aged blokes shuffle about on stage twiddling knobs equals an hour of boredom for your average punter, the pair enlist a cohort of performers, dancers and musicians to turn a Basement Jaxx show into a proper performance. "This year we're bringing a drummer, a percussionist, lots of singers - five or six, I think - and a brass trio," says Ratcliffe. There were no complicated negotiations between Worthy Farm and the Jaxx camp, adds Buxton. "They said: 'Do you want to move up the bill?' and we said: 'Yeah'."
Everything in the world of Basement Jaxx seems to be pretty laid-back. They take life in their straggly, slightly shambolic stride. Twelve years they've been knocking about together now, and it shows. It's not so much that they've aged, more that they do that twin thing of finishing each other's sentences and talking a lot in the first person plural. They maintain that they're very different though. "I don't like interacting with strangers much," says Ratcliffe. "Felix thrives in the company of others, whereas I'm probably someone who flourishes better in a small dark room with a computer." Still, he says rather sweetly, "We're each other's longest lasting relationship."
They're also one of the only dance acts from the 90s still doing something interesting - and commercial. Dance bands always seem to have short shelf lives; good for a few hits and a PA club tour at most before being consigned to the line-up slot on Never Mind the Buzzcocks. But Basement Jaxx just seem to get better and better.
"It's because we've never really aligned ourselves with any one scene," says Ratcliffe in his measured, quiet voice. "When we started, as is always the case, people tried to pigeonhole us, to categorise us, and we've never really been happy with that."
This restlessness can work against them, says Ratcliffe. "It's like, if you buy an album by the Chemical Brothers or the Prodigy having heard the single, you know, more or less, that the album is going to be the sound of that single, repeated 10 times. We're more haphazard."
This, they claim, is why their recent album was a collection of their singles over the years: to remind people that the chaps behind Where's Your Head At were also responsible for the drastically different, bhangra-influenced Romeo, and the latest single Oh My Gosh. "We get bored of doing one style," says Ratcliffe. "We're restless producers, basically."
More than that, they also have a rare, Cathy Dennis-like pop sensibility. "We instinctively know when we've written something that'll sound good on the radio," says Ratcliffe. That said, at the beginning of their career, the duo came very close to going in exactly the other direction. "When we signed to XL [originally the Prodigy's label, now a subsidiary of the major independent, Beggars], we were thinking of signing to Talkin' Loud, Gilles Peterson's label," recalls Buxton. "He'd have really got into our abstract, jazzy side and pushed us in that direction. We could have appealed to beard-stroking Japanese guys, but we went the other route. It's wanting to do something that is part of popular culture, I suppose."
The band's beginnings were far from the Radio 1-friendly tunes for which they are now famous. "In the beginning," says Buxton, "people weren't interested in what we were doing at all." That's because they were too busy apeing the American underground house artists like Masters at Work to bother with British trends. Indeed they packaged their EPs to look like imports while Buxton began calling himself Felix B.
Though they might duck away from the "dance" label ("What is dance music? Is it something with a beat? This whole dance thing pisses me off," says Buxton), they say the best thing about the scene is the lack of pretension. "It's less about ego and more about the crowd and getting a bunch of people together," claims Buxton. "You really notice when you're doing big festivals with all the rock bands that they're a lot more self-conscious and into themselves, checking their fringes and making sure they're always looking cool enough.
"I never thought we'd have commercial success at the beginning," he adds. "What we were doing seemed very off to the side of what mainstream culture was into. It was nothing to do with the British dance scene, which was very much about cocaine."
Both men declare themselves delighted with their mainstream achievements. Especially Buxton, who was recently reminded by a woman he knew from college of something he'd once said. "I'd forgotten about it, but back then I declared that I would have a number one record one day."
And they have had number one albums, played around the world to millions of people and, best of all, received a Grammy from Cyndi Lauper earlier this year. It was Buxton's all-time pinch-me moment, "sitting there with a bunch of booted and suited Americans taking the whole thing very seriously". It was like Glastonbury, they say. "We came through the back door."
· Basement Jaxx: the Singles is out now on XL. They headline Glastonbury on Sunday June 26.
· The Guardian sponsors the Glastonbury Festival. For the latest festival news see theguardian.com/glastonbury
