Girls Aloud are Britain's biggest pop sensation - so, naturally, they're all the rage in Westminster. John Reid, the Home Secretary, was recently pictured with them on the front page of the Mirror, having rushed over to declare his love at the newspaper's Pride of Britain Awards. (A member of Reid's entourage later asked for an autograph on his behalf.) David Cameron, in his down-with-the-kids interview for Radio 1, was asked which one of the band he fancied. He replied delightedly that "it is impossible to choose", before nominating the feisty Cheryl Cole. Ken Livingstone went one step further and took the whole band on a diplomatic trip to Shanghai, as "cultural ambassadors for London".

But the Girls have a complaint: none of their high-powered admirers has actually bothered to ask them what they think about politics. With three albums and 13 top ten singles already under their diamanté-studded belts, they believe they could tell ministers a thing or two about communicating with the apathetic younger generation. Thus it was that I was summoned to conduct "Girls Aloud: the politics interview" at a plush central London hotel suite with the bandmates Cole, Nicola Roberts, Nadine Coyle, Kimberley Walsh and Sarah Harding.

The Girls are, as one would expect, immaculately styled - all carefully angled red berets, airbrushed foundation and racy stilettos. But although they look as if they have just stepped off the set of Footballers' Wives (Cole is, in fact, married to the England player Ashley Cole), beneath their well-groomed exteriors lurks a surprising passion for politics. "We need to make politics more user-friendly," says Harding. "It just isn't talked about in normal magazines and newspapers. We never get asked who we would vote for. It could be a general question to ask us in an interview, but it isn't. Everyone has ideas about what we want for the country, but people need to vote to make that happen."

So, the big question must be: will Girls Aloud back the new-look Trendy Tories? The answer, David Cameron will be disheartened to learn, is no. "Absolutely not," says Cole. But the news for future Labour leaders is none too heartening, either: there is some confusion about Gordon Brown's identity. One of the bandmates is convinced the Girls have met him, while the others assure her that, in fact, Reid is the one they met. So much for the Chancellor's popular appeal.

But how should today's politicians go about engaging the young? The Girls are keen to lend their support. "They need people like us to go into the schools and help spread the word," says Cole. "Our fans would definitely listen to us. They'd think, well, if Kimberley and Cheryl and Nicola are interested in it, then I want to know about it.

"Politicians know that we get listened to by more young fans than they do. That's why David Cameron said he fancied me. He was just trying to be cool. I bet he couldn't name a single song of ours. Do I fancy him? No! Politicians should stop trying to be cool and get on with running the country."

Improved relations with the media are central to the Girls' political agenda: there is a general consensus that neither BBC2's Newsnight nor Question Time is ever going to get through to a generation raised on soaps and Celebrity Big Brother. "There should be adverts in the breaks during Coronation Street spelling it out in bullet points: this is what the Conservatives stand for, this is what Labour stands for," says Cole.

And Roberts chips in: "I know there are programmes on late at night, aren't there, when they have like debates and stuff. But young people are not going to sit there and choose to watch them. It's boring. No 18-year-old wants to watch Gordon Brown doing his whole speech - turn it over! They need to make it more interesting."

Politicians should take note; when it comes to winning votes from the public the Girls know what they are talking about. The group was formed on a reality-TV show in 2002 in which contestants were eliminated through a public phone-in each week. These five were such a hit that not only did they win the competition, but their debut single, the catchy "Sound of the Underground", went on to become the Christmas number one that year. Since then, turbo-powered pop tunes, canny marketing and an award-winning press strategy have ensured that their three albums and 13 top ten singles (the Spice Girls had only ten) have attracted an overwhelmingly positive critical response. Broadsheets have raved; tabloids have lusted. It is the kind of public profile many politicians would kill for.

But is the politics really all about spin, or is there some substance to the Girls' manifesto? Their stance on social issues is broadly old Labour - although Cole admits that "I only vote Labour because me mam does". Indeed, their grip on the intricacies of party politics is shaky at best. As Coyle says: "You know that basically Labour is the working class and the Conservatives are the really, kind of, upper class, and then everything else is . . . I have no idea."

Still, the Chancellor would be pleased that the Girls, unusually for anyone in the pop world, support high taxation. "You'd happily pay taxes if you thought, I'm paying them so a fireman or a nurse can have a decent wage," says Walsh. "People just want to know it's going to the right people." Cole adds, a little peevishly, that she would "love to see a breakdown of exactly where our taxes go. We're in the highest tax percentage, so our earnings are nearly halved."

They also recognise the need to tackle social exclusion. Cole was brought up on a Newcastle council estate, and says that "since being in the band, I have grown up a lot. I take more notice of what's going on in the world now, because I feel more a part of it. But when I was growing up I did not have a clue. All I knew was going to school and going back to the council house, not always being able to have dinner, not knowing why we were skint, just assuming that's the way things had to be."

To Girls Aloud the National Health Service has high priority - and new Labour's plans for it take a hammering. "They say they're going to do all this stuff for the NHS but it goes on paper-pushers," says Coyle. "The money's not actually being spent where it's needed. My friend in Northern Ireland has been in education for eight years, training to be a nurse. She's working at Great Ormond Street now, but she has to live in a communal hostel because she can't afford anywhere else. She's so disheartened that she has decided to go back to Northern Ireland. At least there she can have a decent standard of living."

"These people are needed," says Cole passionately. Besides, she argues: "It puts the younger generation off going into that profession, because there's no money in it."

On education, however, the Girls diverge sharply from the traditional left: they are strong advocates of grammar schools. Coyle, who grew up in Northern Ireland, attacks the English comprehensive system. "Northern Irish schools always seem to turn out better results," she says. "They made us aware of our heritage and of Northern Ireland's politics. But politics is huge over there - you have to vote all the time, and you can see the difference in your community if you vote for Sinn Fein or someone like that - you see the importance."

"You can't help the fact that some kids are just not going to be as bright as others," agrees Cole. "If you're sitting with people who aren't as bright as you, you're going to get frustrated. And then people wonder why there's so much truancy. They should definitely bring back grammar schools. Then you can say to low achievers: you can get there if you work hard."

The bandmates' take on gender issues is distinctly post-feminist. When the Spice Girls conquered the pop world ten years ago, they brought with them lofty concepts such as "girl power". Girls Aloud are not so idealistic. "I think that's all gone. When the Spice Girls went, girl power went, too," says Cole. "They didn't actually change anything. It's bad really." The young girls who follow them, they admit, are more likely to aspire to marrying footballers and living luxurious lifestyles. "It's the media that put them in that state of mind," Cole says. "They make it look really glamorous : you can go out and sit on your arse and have all the jewels you want. It's a joke. These women have nannies, they don't cook a meal for their husbands, they don't clean because they've got a cleaner, they have all the handbags they want but never do a day's work. What kind of aspiration is that? Footballers' wives are just as bad as benefit scroungers - it's just a higher class of sponger."

Yet, like for many of their generation, the defining issue in their perception of contemporary politics is the war in Iraq. "We are too young to really remember the excitement of Labour getting into power," says Cole. "All we know is what's happening now, which is that Blair equals George Bush and the war in Iraq. So you wonder, why did he take us to war? Why did he agree to that? It affects the young more than anyone because they've got to go out into it."

On that point if no other, even many Labour politicians would admit that Girls Aloud are talking more sense than the Prime Minister.