The people carrier has been ferrying Girls Aloud around West Ham for a matter of moments when the inevitable happens.

They are being followed. Paparazzi.

“He can’t be a very good one,” notes Kimberley Walsh, regarding the blue Ford Escort. “Look at his car.”

“Hey,” chides Sarah Harding, “that was my first car.”

Girls Aloud have spent the morning having their hair, make-up and wardrobe attended to in a nearby hotel. Now that they’re reliably glam, the Times photographer is taking them to locations that are just the opposite.

Sarah phones her boyfriend, DJ Tom Crane. “Tommy says we want to be very careful around here because it’s rough as f***,” she announces. “And he’s from Hackney.”

They stop outside a boarded-up nightclub: Twilight.

“This is a s***hole,” affirms Nadine Coyle.

“Aw,” says Cheryl Cole. “What a smell of stale p***.”

They pose for photos. A VW convertible slows and a man leans out of the passenger window. “Nice arse!”

“What a d***head,” mutters Cheryl.

At the next location, a police car stops to have a look.

“He’s come to breathalyse you, Sarah,” chuckles Nicola Roberts of her bandmate, a fixture in The Sun’s “Caner’s League”.

The photographer shows them a Polaroid. “I look like Pauline Fowler,” Sarah sighs.

A middle-aged woman comes running over. “My daughter said, ‘Stop the car! It’s Girls Aloud!’” She asks them to autograph a copy of Jackie Collins’ Lovers & Players. “It’s the only thing I could find that we wouldn’t throw away,” she explains.

Back in the people carrier, the paparazzo reappears.

“Here he comes,” notes Cheryl. “Chitty Chitty Bang Bang.”

“The time you’ve got to worry is when nobody wants to take your picture,” she says, tapping her head with her tattooed right hand for emphasis. “That’s the only way to deal with them – mentally.”

Back at the hotel, there are remnants of a breakfast buffet. “I’m taking that melon home,” announces Nadine. She drops it in her bag. “Does anyone want that pineapple?”

These are just some of the reasons to love Girls Aloud.

To call Girls Aloud the most successful female group Britain has ever produced is an unassailable truth. All their 16 singles have shot into the Top Ten, a feat that eclipses, say, the Spice Girls, who managed ten Top Tens, and one that last month earned Girls Aloud a Guinness Book Of Records nod. But it also damns them with the faintest of praise. Thanks to a combination of peerless pop music, an enthusiasm for speaking their minds and an absence of anything that might even vaguely be considered media training, Kimberley Walsh (25, from Bradford, pre-fame acting career peaked with TV’s This Is Personal: The Hunt for the Yorkshire Ripper), Sarah Harding (25, from Manchester, enjoys a flaming sambuca “but I’m not always as p***ed as the photos make me look”), Nadine Coyle (22, from Londonderry, currently pursued by both tights and razor companies on account of her fathomless legs), Nicola Roberts (22, from Runcorn, just abandoned Malcolm Gladwell’s Blink – “I couldn’t be arsed”) and Cheryl Cole (24, from Newcastle, formerly Cheryl Tweedy and Boots’ Bonniest Baby), have found themselves hailed not just in all the usual forums – the world of heat’s Flattest Stomachs and FHM’s 100 Sexiest Women In The World – but in places that have little truck with shiny girl groups: NME, The New Statesman and Jo Whiley’s Live Lounge. They have collaborated with Franz Ferdinand, been covered by Arctic Monkeys and stormed the rock-centric V Festival. “We were like, ‘Who from the record company decided we should do this? No one’s going to show up. People are going to start throwing bottles of p***,’” says Nicola. “But it was the complete opposite.”

“They are simply the most perfect pop group since the Monkees,” says Julie Burchill, a fan who coined a new genre in their honour: panty-liner punk. “Proof that chav culture can wipe the floor with middle-class pseudo-intellectualism any day.”

“Girls Aloud highlight the very lively, colourful aspect of pop culture people associate with the UK,” says Mayor of London Ken Livingstone, who last year invited them on a diplomatic trip to Shanghai, promoting the capital. “They were brilliantly received and great ambassadors for London.”

“They’re the best,” says Arctic Monkeys’ Matt Helders. “Their songs do really musical, clever things; the stutter-rapping in Graffiti My Soul… They’re unbeatable.”

Yet Girls Aloud’s achievements become all the more remarkable when you consider their origins: thrown together as winners of 2002’s Popstars: the Rivals, a dimly remembered forerunner of The X Factor. “We got dropped out of the air, the five of us together,” says Kimberley. “A clash of personalities, ages, backgrounds, everything; but it works.” They remain reality music telly’s only real success.

By contrast, their co-winners, boy band One True Voice, fell apart after just two singles. One was called Shakespeare’s (Way With) Words.

“I don’t think I’d have been any more frightened if I was put in a line-up to be shot,” says Cheryl of the experience. “But to be critically acclaimed from where we came from, we struggle to cope with that. I don’t know why people bothered to stick around.”

Indeed, with Top of the Pops being axed, Smash Hits going down the dumper and enthusiasm for “manufactured” chart bands evaporating, the cultural wind was hardly blowing their way. Today they could stake a fair claim to be Britain’s Last Pop Group. “Imagine a time when there was All Saints, Blue, Steps; there must have been a totally different vibe,” says Kimberley. “We’re the only ones left. We’re keeping pop alive.”

Cheryl is characteristically more forthright: “I think the whole music industry is going down the s****er.”

Girls Aloud remain unclonable; proper mates who spend “loads of time together, loads”. “You couldn’t create it,” says Kimberley. “The relationship between the five of us, the journey we’ve come on, our relationship with Brian…” Brian is Brian Higgins, the maverick producer who heads up songwriting team Xenomania. Having written Believe for Cher – Number One in more than 20 countries in 1998 – Higgins ensured that he’d never have to do a day’s work again. Instead, from his Kent mansion, Xenomania and Girls Aloud conspire to make increasingly ambitious, thrillingly out-there pop music. Hits like Something Kinda Ooooh (Sixties girl-group goes rave) or Sound of the Underground (Dick Dale surf-rock meets drum’n’bass) pack in more ideas than a whole album by, say, Klaxons. Their lyrics, meanwhile, offer something other than manufactured pop fare. It’s difficult to picture Leona Lewis, for example, singing Racy Lacey’s, “She’s made seduction a work of art/ A PhD with her legs apart”.

“Brian draws from our personalities and puts it into the songs,” says Sarah. “That’s why it works.”

Next month they’ll mark their fifth anniversary with Tangled Up, an album featuring a subtle maturing of their sound. “It’s more grown-up,” notes Cheryl. It’s been preceded by Sexy! No No No…, the video for which did indeed feature the girls appearing more grown-up, in PVC. “But we didn’t set out to look like dominatrix [sic],” insists Nicola. Elsewhere, Call the Shots, I Can’t Speak French and Fling offer more food for thought. “The politics of relationships, infidelity, hedonism, female overconfidence and weak men,” says Brian Higgins. “In five years their lives have changed completely, yet they’ve been going through the same issues as their peer group. They are not [as Love Machine had it] ‘gift-wrapped kitty kats’ any more. It wouldn’t work if they sung songs pretending they were.”

At Christmas, they’ll appear with Colin Firth and Mischa Barton in the St Trinian’s remake, as the “naughty” school band “in stockings and suspenders and that”. And in February, ITV2’s Passions will feature the girls apparently fulfilling lifelong ambitions: Cheryl “street-dancing” in Los Angeles; Kimberley trying West End musicals; Nicola creating her own make-up range; Sarah learning polo in Argentina; Nadine conducting a classical orchestra. That last one sounds pretty interesting. “I was pretty interested to hear that too,” chortles Sarah. “She’s conducting an orchestra?”

Another day, another photo shoot. This time for a girls’ monthly. In a North London studio, four fifths of Girls Aloud have been done up in a look that might be described as Hallowe’en-inspired, if Hallowe’en took place 300 years in the future. “It’s the most ridiculous hairstyle I’ve ever had,” sighs Kimberley. Their interview begins, “What’s the most annoying habit each of you has?”

Sarah is off ill. But she’s in today’s paper, “the last to leave” West End celebrity haunt Mahiki at the weekend. Meanwhile, Cheryl spent Saturday with her husband, Chelsea and England footballer Ashley Cole, celebrating the national side’s 3-0 win over Israel by “flying around the players’ lounge, getting extremely drunk and embarrassing myself”.

“It should be the players who celebrate,” she notes, “not me.”

Which brings us to the other Girls Aloud – their tabloid doppelgängers. Seemingly no day passes without this parallel five getting embroiled in some headline-hogging drama, a past month of which includes (but is not limited to): Cheryl Cole Tells How She Wrecked Ashley’s Career Move… Sarah Harding Moves DJ Lover Into New £1m Pad… Nadine Coyle’s Boobs Bigger Now She’s Back With Jesse Metcalfe… Cheryl Cole To Go Solo. And so on.

“The fame side of it can be horrible, to be honest,” Cheryl says. It’s true that much of the spiteful stuff seems to be reserved for her, perhaps because an early, unfortunate altercation with a Guildford toilet attendant over complimentary lollipops seemed to mark her out as trouble (she was charged with assault but cleared of racial aggravation), more likely because of her husband.

“The tabloids have always had a thing about me because I speak my mind,” she reasons. “I struggled with being called nasty things, because it was all new to me. Where I’m from, if somebody from the northeast does well, you’re happy for them. Growing up, I was a well-liked person who got on with everybody. Now it’s a relief to read anything nice. Somebody called me ‘immensely likeable’ the other day. I haven’t heard that since before I was famous.”

One paper was recently agog with the revelation that she had to teach Ashley how to boil noodles. Surely he could manage?

“He can’t,” she insists. “He’s absolutely pathetic. He deserves to be exposed. He makes me a nice cup of tea in the morning, though. I’ve got him well trained.”

Cheryl’s notoriety has hardly been discouraged by a series of pop-star spats. There was Charlotte Church, with whom she traded barbs on everything from musical plagiarism to skirt lengths.

“I’m gutted about it. It came from a misconstrued comment and it spiralled out of control. I actually really like Charlotte.” Can’t they make up? “If Charlotte wants to speak to me, I’m more than happy to apologise to her face for whatever I’ve said. But whether or not she accepts that…”

Then there was Lily Allen. “She called my husband ‘horrendous’ and I didn’t say anything. She had a go at Sarah and I didn’t say anything. And then she called Nicola ‘ugly’. For another female artist to call you ugly is so awful. Nicola’s been called ‘ginger’ all her life, then she makes something of herself and everyone called her ‘the ugly one’… I feel very protective towards her, and if that means I’m going to call Lily whatever [“a chick with a dick”, on TV’s The F Word] then I don’t care. Forget about her calling my husband horrendous, she can say what the hell she likes about that. It’s ridiculous.”

Why “horrendous”?

“You’d have to ask her that. I used to actually quite admire her. She had a song called Cheryl Tweedy [‘Wish I looked just like Cheryl Tweedy/ I know I never will…’]. I thought it was complimentary. Then she said, ‘I was being ironic. Nobody wants to look like that.’”

“If she said anything to my face,” says Sarah, “I’d probably lamp her.”

Recent tabloid reports suggest that Cheryl and Allen may have patched up their feud. In any case, there is one person who gets Girls Aloud’s goat even more than she does.

“Pete Doherty is a p****,” says Nicola. “He was in the paper giving his little kitten crack cocaine. I’ve still never heard one of his records. [Sceptically] Apparently he’s a really good poet.”

“He’s not a poet,” says Cheryl. “He writes s***. He’s a waste of fresh air. Why is he such a genius? Cos he went out with Kate Moss? And he gets let off from jail. Kids look up and go, ‘Oh, he doesn’t even get locked up.’ More deserving people are on the waiting list for methadone every single day…”

Drug abuse is a big thing for Cheryl. She dated a heroin addict, her younger brother was involved with drugs and, in 2005, a close friend overdosed, aged 21. At his mother’s request, the papers published a photo of his corpse. The needle was still in his arm.

“Heroin was there for the taking. I could easily have taken that route if I’d wanted to. But I always maintained my ambition and I’m proud of myself. I wouldn’t be sitting here with an amazing husband and an amazing house. That nightmare devastated family and friends, but I’m grateful. If I hadn’t been exposed to that at such a young age, who knows what might have happened?”

How have we got to the stage where photographs of celebrities shooting up are served up as entertainment news?

“It’s like the Mickey Mouse Club, and it’s not f***ing funny. Heroin’s the latest trend. The pictures are horrifying, but teenagers don’t see it like that. They think [celebrities] are having a wild time, living this amazing life.”

She says she’s “devastated” Amy Winehouse “has gone down that road”. At some point, after Girls Aloud finish, she wants to set up, and put her name to, a support network for addicts’ families.

“I don’t have any sympathy for the addicts. That might sound harsh, but I really don’t give a f*** how they feel. If they’re in pain because of drugs, it’s self-inflicted. You know what you’re doing when you take it.”

There’s an uncomfortable pause. It becomes apparent that Cheryl is trying to prevent herself crying. “Amy’s dad is doing his utmost…” she says, but never finds the words.

So we talk about David Cameron instead. In a move that was by no means creepy, last year the Leader of the Opposition told Radio 1 he found it “impossible to choose” which member of Girls Aloud he fancied most, but twist his arm and he’d plump for Cheryl.

“I laughed and laughed,” she says.

“I find David Cameron quite funny, actually. He tries to be cool. I find him quite cute.”

Cute probably wasn’t the reaction he was hoping for.

“Yeah, maybe. Still, it’s always nice if somebody thinks you’re pretty.”

Cameron might have had more luck with Nicola. After she sounded off over the shooting of 11-year-old Rhys Jones – a fellow Liverpudlian – one tabloid found that 96 per cent of its readers thought she’d make a better Home Secretary than Jacqui Smith.

“I was made up with that,” says Nicola, cheerfully.

At any road, she’s not much of a fan of our PM. “He’s never really lived, has he? Gordon f***ing Brown going on like he’s going to be the next Thatcher. Please: don’t feed us full of s***.”

Labour are, she says, “all talk and no action”. “The whole country is going to s***.” The answer? Compulsory public service.

“What’s the point in voluntary service? You’ve got this opportunity to do public service and work your guts off… but you don’t have to if you don’t want to? You can hang around the park?”

The problem is, there’s just no discipline any more.

“And there’s no… Britishness. You’ve got Tony Blair saying, ‘Don’t fly your flag.’ Why not? Would the French president say, ‘The British don’t like it, don’t fly your flags’? No. So why is it happening in our country? I agree you should modernise the country, but I don’t think you should lose all our strength and culture.”

Under Margaret Thatcher, she says, “we had the best army in the world”.

Is she a Thatcher fan? “I am a fan, yeah. She was a very strong woman and that’s admirable.”

So the Conservatives can count on her vote?

“Yes. Because the soft approach on law isn’t working.”

Girls Aloud know they won’t be around for ever. “I think it’s a bit silly running from left to right singing, ‘I’m just a love machine’ when we’re 30,” splutters Nicola. Eventually, she says, she’d like to be more involved in songwriting. Nadine, already LA-based, wouldn’t rule out acting, travelling or a solo record. And Sarah wants to buy a big house in the country “and get Tommy a dog”.

The last time I speak to Cheryl she’s been enjoying LA, filming her “street-dance” programme and trying to stop her mum shopping for Juicy tracksuits.

She has this to say about the future. “We’ve all grown into young women in the public eye. We genuinely are best friends. If it ended, I think I’d shrivel up into a ball.

“Looking back,” she says, “I don’t know how I lived without the girls.”

Girls Aloud’s new album, Tangled Up, is released on November 19 on Fascination Records. To hear chief pop critic Pete Paphides in conversation with Girls Aloud, go to timesonline.co.uk/music

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