The Strokes: The reinvention of New York's coolest band

What do you do after being acclaimed as the coolest band on the planet? If you're The Strokes, you cut out the booze, grow up and try to achieve perfection

Who'd have thought it. Not only does Julian Casablancas have a favourite joke, but he giggles like a silly school boy as he reveals its decidedly lewd punchline. This really isn't the sort of behaviour we've come to expect from one of the coolest men in rock - more usually seen looking the epitome of a rock icon, in tight jacket and aviator shades, effortlessly holding court over roomfuls of adoring fans at sold-out shows.

From the moment the band crashed onto our shores in 2001 with the sonic slap-in-the-face of their debut, Is This It, they were hailed as the future of music. Impeccably dishevelled in their dirty Converse trainers and crotch-clinching jeans, the unassailably cool New York five-piece were embraced as rock gods and venerated as such. They had the tunes, the looks and in the case of drummer Fabrizio Moretti and guitarist Nick Valensi, the celebrity partners (Drew Barrymore and Amanda De Cadenet, respectively). The Strokes made guitars exciting again, utterly reinvigorating a stagnant rock scene. Five years and over a million record sales later, the band still command both curiosity and respect - enough to send, their third album, the muscular First Impressions Of Earth, to the top of the album chart on its release in January. In this fickle, big-today-gone-tomorrow climate (hello The Darkness!) that's no mean feat.

In person, though, The Strokes aren't as nonchalant as you might imagine. The band are in the midst of a 17-date sold-out UK tour and in just a few hours they're due on stage at the 2,500-capacity Glasgow Academy. But although the fab five are very pleased with the way their new songs are going down each night, Casablancas is taking nothing for granted: "I experience performance anxiety every night," he says. "Every night as I walk to the stage I feel, like, 'What the hell am I doing?' I feel like I'm being led to my hanging!"

Of course, come the show, Casablancas' nerves are imperceptible and the band look like they've rolled off their bar stools straight onto the stage. But the powerful show proves that The Strokes have raised their game. With Casablancas off the booze, drunken performances like their fist-bitingly bad V2004 appearance, are a thing of the past. Indeed, the band have recently taken to rehearsing before shows: tonight, they've managed to cram a drum-kit and a small forest of guitars into their tiny backstage dressing room.

Instead, Casablancas has a general determination not to rest on his laurels. "It's important to always know you can do better," he says. "You can enjoy your success, but I found that's very unhealthy. It's like the devil almost: it says, 'Look what a great thing you've done, relax, enjoy it,' but every second you waste doing that is a second you haven't put into doing the thing that you're really going to be proud of. Being over-confident only tricks people into being mediocre - you just end up screwing yourself up for the future."

Casablancas talks like a man singed by experience. The Strokes are aware that their highly anticipated second album, 2003's Room On Fire, failed to live up to expectation. It shifted 350,000 copies in the UK, hardly risible, but less than half what their debut sold. "We fell into a lot of traps making that record," admits affable drummer Moretti. "Not that we got lax, but in hindsight we were trying too hard to live up to the hype of the first album."

Room On Fire was almost like a photocopy of Is This It - largely similar and certainly not bad, but lacking the striking quality of the original. But the album's comparative failure sharpened the band's resolve. "We realised people couldn't avoid the sonic similarities of the first two records," says bassist and Casablancas' childhood pal Nikolai Fraiture. "We told ourselves that if the third album sounded like the first two it would give people the right to say: 'I told you so, they're a one trick pony.' We needed to make a third album that would open up the possibility of an actual musical career."

Nearly twice the length of their first two records, First Impressions Of Earth is very much the record they wanted - and needed - to make. Equal parts rock brawn and pop nous, it's the sound of The Strokes beefing up their taut garage-pop to almost Muse-like proportions. And while the album won't define a generation like Is This It did, it is the sound of a defiant band exploring their potential, flexing their musical muscle and proving their worth.

Not that there has been any popping of champagne corks chez Casablancas. "A few more songs could have been something special," he says, "but I didn't have the time to make them really live up to their potential." That The Strokes really care about their music has been well documented, but there's an ulterior motive to Casablancas' perfectionism that is less known: "I want to get better at my music so that I don't have to justify myself to journalists anymore," he says.

Casablancas finds interviews excruciating. "Doing press is like talking to a bunch of bad psychiatrists," he chuckles. "It's so draining when every time you're talking to someone you know what you're saying is being judged." Today, the band's management tell me, is an unusually talkative day for the singer. Forthcoming, honest and genial, he comes across as awkward rather than arrogant. Indeed, his long, meandering sentences make it abundantly clear that, off-stage, he's not your usual limelight-loving front man. "I'm not very good at banter," shrugs Casablancas. "People can say I'm vague and don't have anything to say and that's fine. But until I can express myself perfectly, I won't feel comfortable talking to people."

Is he happier now that The Strokes are no longer in the eye of the hype storm? "I don't know," he says. "I think we want that commercial success but... I don't know." He shifts in his chair, scratches his nose, crosses his arms and tries again: "I'm in two minds about it. Half of me wants to have some mega hit so that we can be legitimised. Like when people win Grammies - the achievement somehow says to the majority of earthlings, 'This is good music'. But in another way, my favourite things are usually underground things, so the other half of me feels that if we work hard and what we do is good, I shouldn't worry about that other stuff."

"I was grateful for all the hype at the time," explains Fraiture, "but I hope that now we're thought of as a band that make good records and play good gigs, rather than faces in magazines or people who wear certain clothes." Moretti agrees: "Without the frivolous hype we can build our niche and then maybe in the future we can be remembered for our music. We might not be a grandiose horse of a band, but we could be a pretty strong steed."

"People care about us in a different way now," continues Moretti, a man fond of his metaphors. "The way I look at it, it's like buying a new pair of roller-skates, the first day you get them, you're like, 'Wow, these are great - the wheels, they look beautiful.' And then maybe a year later, they're all scratched-up and they look like they've been through the ringer. But you love them almost more than you did the first day because they remind you of all your skating memories. That's us. We're roller-skates. But then rollerblades come along. Rollerblades were influenced by roller-skates - maybe they're like the Arctic Monkeys!" he laughs. "Maybe rollerblades will destroy us!"

Now that the fickle, fashion-led fans have turned their attention to the Arctic Monkeys, The Strokes have been left with a reduced, though still significant, army of what Moretti proudly calls "rock-steady fans". "They sing along to every single word," he says full of his puppyish enthusiasm. "And if they don't know the words, they pretend to! I can see them, mouthing randomly. It's very endearing."

Tonight, throughout The Strokes' mammoth 22-song set, the 2,500 rock-steady fans are in fine voice. As is Casablancas; where in the past his vocals could be muddy and undecipherable, now they're pierced with clarity. The venue bounces like one big indie disco and beer is spilt with reckless abandon. There's not much in the way of banter, just the occasional Elvis-esque, "Thankyouverymuch". But The Strokes, like their crowd, are glowing with exhilaration; by the end the whole band are jumping around and - get this! - grinning. It's abundantly clear they're having a whale of a time.

After the gig, wearing hotel slippers (his boots are wet) and nursing a beer in the hotel lobby, mop-topped guitarist Albert Hammond Jr is still buzzing. Shows in media hotspots like London, New York and LA are rarely as enjoyable as tonight's: "You can't really let go; you feel you're being judged," he says. One by one, his band mates join him. They tease Valensi about his sweet tooth - he's got a chunk of caramel toffee cake he's going to eat in bed later ("It feels less guilty that way," he says) and discuss how they'll spend their day off tomorrow. It's a toss up between getting some sleep and visiting some art galleries. Not exactly classic rock'n'roll pursuits.

The Strokes, it seems, are growing up. Moretti agrees: "A lot of things that were a lot of fun back in the day have changed," he says. "Like this feeling that we'd live forever, confidence in ourselves that's brought about by youth, stuff like that. We're a little bit more settled now, a little bit more responsible about ourselves, but we've kind of gone through certain challenges that have made us stronger. As a band. And as friends."

The five-piece realise they're not the white-hot property they once were, but as musicians - and as friends - they are tighter and, they insist, they're having more fun. And while they're genuinely proud just to have outlived their albatross-like hype, The Strokes' appetite for success is far from sated. "We've got so much left to do," says Casablancas. "We're still trying to get somewhere higher." The Strokes don't want to be remembered for being a hyped band or for being a cool band. They want to be remembered for being a great band.

'First Impressions Of Earth' is out now. The Strokes release 'You Only Live Once' on 10 July and play Manchester Old Trafford Cricket Ground on 18 June, Wireless Festival on 21 June, Oxegen Festival on 8 July and T In The Park on 9 July. See www.thestrokes.com for details.