"What we like is not where we need to be on the show because it would just completely misfire," explains 28-year-old Murray. "You have to massage where you are and what place you're in. Within the more clued-up London circles you could be forgiven for thinking that the Kaiser Chiefs are a massive band that everyone loves and to this day they're not. When you work in mainstream at Radio 1 you realise after a while that 'leftfield' is probably situated more around Gwen Stefani in the minds of the greater public."
The Kaiser Chiefs' debut album Employment sold more than a million copies and won them a Mercury nomination, which hardly marks them out as niche listening, nor do Stefani's chart-topping releases put her on the margins of the British music scene. But Bowman, 30, says that the music they play needs to be something "familiar, that John driving his van and Stacey at uni can relate to". Perhaps that's why she was pleased to find Britney Spears' "Toxic" on their playlist the previous day. They both insist that McFly are credible "because they play all their own instruments" and that Girls Aloud make cracking pop records.
Still, the fact they had been out together the night before this interview watching an indie band called The Crimea suggests the pair are not as mainstream as they would have their listeners believe. This band, as well as Tom Waits and Nick Cave, whom Murray cites as personal favourites, and Arcade Fire, of whom Bowman is a huge fan, would be lost on their target audience. Bowman sums up this audience with an email she received from a listener: "The nicest email I've ever read about the show was a girl who'd had the shittiest day at university. She came back to her halls of residence and she switched on the radio, and she felt like she had mates in the room with her. That's what we want, for people to feel part of the show and for us to be there with them."
"I don't think it's the funniest show and I don't think it's the cleverest show," says Murray of their down-to-earth presenting style, "but people say, 'I can have a drink down the pub with them.'" So easy is the relationship between the presenters and their fans, he continues, that "we're in a situation where they view us as mates".
And this is how they've always been, says Murray. They pull in more than 5.5 million listeners every week - figures which have increased at the last two official counts - because of the natural, unscripted nature of their show, which features two best mates gossiping with whomever fancies calling in for a chat, be it about music, relationships or bikini waxing.
"I think 'unpretentious' describes most Radio 1 listeners," says Murray. "I don't think the station ever pretends to be too cool. It never tries to force anything down anyone's throat. It's not about tuning in to join a club, to wear certain clothes or have a particular profile."
He and Bowman are at pains not too appear "too cool" for their listeners, but insist it comes naturally. "We're not patronising our listeners," says Murray. "We've not moved our profile. The show's doing well but we're not getting listeners in that way. We're not in a celebrity circle and we don't go out three nights a week and put coke up our nose."
They may not have "moved their profile" but it's never been particularly boy-and-girl-next-door - their previous work was in television presenting. The pair met hosting the ill-fated RI:SE, Channel 4's much-derided morning show, which gave a gaggle of wannabe celebrities, including Big Brother winner Kate Lawler, a shot at live presenting. Though they both have negative memories of working on the show, Bowman is mindful of the experience and exposure it gave her, and it brought their faces to the attention of Radio 1 controller Andy Parfitt, who threw them together for a weekend show in early 2003 before promoting them to their current slot a year later.
Murray is certain that his listeners don't think of him as famous and that gossip magazines "have no interest in us on a celebrity level". But Bowman, who has experienced being chased home by paparazzi, admits, "I know I do a job that's in the public eye and I appreciate it. I know that the public owns part of me in a sense and it has a right to that."
However anxious they may be to drive home their ordinariness, outside of Radio 1 the pair have been busy filling out their CVs with high-profile presenting work including Glastonbury as well as charitable television capers: Bowman won Celebrity Fame Academy earlier this year, and Murray impersonated Mark Knopfler on Celebrity Stars in their Eyes. The next step is to win back Eurovision glory for the UK, and they say it's not just a rumour: they've written the hit already.
They also say that being a celebrity doesn't necessarily engender good radio. "There are certain shows which have brought in big names, like the breakfast show on Capital. They've brought Johnny Vaughan in who's a massive name and they can't even get a million listeners. And that's because the show's not very good. It doesn't come down to how big the personality is - it's how good your show is."
So they're happy to stick to mainstream music as long as it keeps the listeners tuning in. "I'll never let it get to that stage where you're pushing through the Radio 1 schedule to the point that you drop off the edge and go to 6 Music," Murray says, even though he began at Radio 1 presenting a specialist show in the evening.
"I know what it's like to be able to play exactly what you want," he says. "What comes with that is being able to play two hours of exactly what you want to just under a million people, as opposed to playing two or three tracks a day that you're very, very passionate about to five and a half million people."