The Coldplay story has been well documented in recent weeks. Record companies started clamouring for their signatures as 1998 drew to a close and their debut Brothers and Sisters EP was making waves on the back of high praise from Fierce Panda label boss and NME writer Simon Williams. Steve Lamacq saw them in a pub and immediately asked them to become the first unsigned band to play a session for his Radio One show. Parlophone won the bidding war and Coldplay calmly, collectedly trotted off back to University to finish their degrees.

I first saw Coldplay grinning from ear to ear in disbelief at a straggled mid-afternoon crowd in the New Bands Tent at Glastonbury 1999. They played a confident set of sumptuous, instantly accessible guitar songs rasped and uplifted by the tender, tired voice of Chris Martin. I saw them again supporting Bellatrix on their autumn tour the same year and we sat in a bar and ate Pizza. They could count the number of interviews they had done on one hand and Chris simply couldn't believe that being in a band meant he'd get his pizza for free. He said then, 'We're very keen, and so are our record label, not to be one of those over-hyped new bands, just to build things slowly.' Having watched Coldplay that night along with approximately ten other people, I wrote: 'As a live entity they are an enthralling blend of fizzing crescendos and intimate desolation, a kaleidoscopic swirl of atmospherics and emotions. The music industry roller-coaster has seen the potential and shows no sign of allowing Chris to disembark just yet.'

Our next meeting was at the Sheffield leg of the NME Brats tour. Coldplay went on first and nobody bothered turning up in time to hear Chris announce he had just written a new song, which the band then played for only the second time. That song was called Yellow.

And then…wow.

Yellow's jaunty melody bounded into the charts at an astonishing number four. Coldplay's delicious debut LP, Parachutes, entered the album charts in pole position and suddenly the band was the industry's hottest property. Parachutes has already sold in excess of 300,000 copies and has been nominated for the Mercury Music Prize. In typically bashful fashion, the band released a statement in response: 'We put a lot of effort into making a record that we are proud of and happy with so it's nice to know that other people quite like it too. We always hoped that our record would mean as much to other people as our favourite records mean to us. Our vote [for the Mercury Prize] would go to Badly Drawn Boy because he is brilliant. Thank you very much.' Ah, bless.

When the opportunity arose to interview Coldplay again, post-fame and adulation, I had just finished reading a novel called Powder by Kevin Sampson. In breathless, adrenaline pumped prose, it tells the story of a band called The Grams who move from unsigned ignominy to world domination inside a year and promptly capitulate amidst a maelstrom of clashing egos, casual shags and the dedicated hoovering of copious lines of charlie.

Coldplay are never going to fall into that trap. Chris doesn't even drink and the chances of a Coldplay member being pictured within the postcode area of the Met Bar are slimmer than Shady. But a late-night message which recently appeared on the Coldplay website strongly suggests the fulfilment of dreams is not all it's made out to be. The entry isn't signed but it is tempting to see it as the manifestation of the fragility and insecurity that Chris has only ever previously revealed in his songs:

'It's a bit weird I suppose when everything you have wished for arrives at once. When the album was being made we hardly dared dream about it reaching the top of the charts, let alone it going straight in there. I personally was terrified that it would get ripped apart by the critics. Now we've been number one, had all the hyperbolic praise a band could wish for and yet none of us has been particularly happy. In fact, I for one have been feeling particularly stressed out.'

It's hard to reconcile such a statement with the carefree enthusiasm of Chris Martin six months ago. Everything has changed. The band no longer has time to sit in bars and eat pizza with student journalists. They are trapped in a strangulation cycle of interviews, promotion, signing sessions, TV appearances, fame, fame, fame.

It's just after lunchtime on a Wednesday when drummer Will Champion answers the phone for our scheduled interview.

'Yeah, it's hard,' he admits in dead tones. 'Really hard work. I've been sitting here since 9 o'clock this morning doing phone interviews. We obviously wanted to get our music across to people but this is a tricky period. Our priorities are not our choice of priorities. We formed a band to play music and that is something we're not getting to do at the moment.

That's the crux of it. Playing music secured Coldplay's fame, and fame has stopped Coldplay from playing music. Has the infectious enthusiasm and wide-eyed innocence of the band circa 1999 been eroded and corrupted by the trappings of success?

Will sounds tired. Really tired. And fed-up. But perhaps Coldplay a band who can ride the inevitable storms and cope with the mammoth pressures that drove a fatal stake into the heart of Sampson's fictional Grams and countless other very real bands. As hard as I push Will to denounce the circus charade of promotion, he simply comes back with acceptance and optimism.

'It is just something you have to do and something we knew we'd have to do. I think it just makes everything even more of a challenge. The hunger for success is stronger than ever before and we're all still finding it really exciting. It is such a buzz to see the reaction of the crowd to your songs.

'It can get frustrating, of course. We're anxious to get back into the studio and record some new stuff and we want to get to live a little. Since I've been in London I've only been out about four times.

'But we're our own harshest critics and we put pressure on ourselves more than anyone else. We're quite capable of handling it, especially as we're surrounded by good people. People we trust.'

And this level head belongs to a 21-year-old. Chris Martin is 22, guitarist Johnny Buckland is 21 and bassist Guy Berryman, 22. They were all mates long before they decided to form a band. They stick together. Their manager is Chris' best mate. They decided not to play the Reading Festival because Chris' Dad wanted them to play in his village cricket team. It may be tough going right now, but Coldplay are riding it with impeccable maturity. Carried away? Burn out? They wouldn't know how.

But surely their friendships are being put to the test by the circumstances in which the band find themselves?

'We certainly wouldn't be as good a band if we weren't mates first,' says Will. 'We'd never let anything get in the way of us being mates. We're all very honest with each other and if someone is being a tosser, we just say "you're being a tosser". I think if we bottled it all up we'd just explode. Honesty is definitely the best policy.'

How refreshing. How Coldplay. And so all seems well and good after all. Will is keen to sing the praises of the new Badly Drawn Boy album, which, he says, has been welded to his stereo since its release. He's quietly confident that his beloved Southampton will stave off the threat of relegation yet again and reckons they might even settle down in mid-table, provided the defence shores up it's notorious leaks, of course.

And for the band? There's a 17-date tour coming up in October culminating in a two-night stay at London's Shepherd's Bush Empire. The same month sees the release of the third single to be taken from Parachutes, the desolate ballad Trouble. 'It's our favourite on the album,' says Will, 'but we don't expect it to outshine Yellow.'

'We'll be continuing to promote Parachutes until Christmas time,' he continues, 'and then hopefully we'll go back into the studio. But we'll be playing some new stuff on the tour which we reckon is better than anything we've already done.'

If he's right, the future's bright for Coldplay.