Chris Martin is onstage at Shepherd’s Bush Empire. It’s Coldplay’s biggest-ever headlining gig and he’s speechless. He can see Liam Gallagher standing at the side of the stage. Kylie and Natalie Imbruglia are here too. He looks at his best mates next to him – guitarist Jonny Buckland, drummer Will Champion and bassist Guy Berryman – and wonders if they’re feeling as weird as he is. Then he decides to say the first things that come into his head. He introduces their encore with: “OK then, we’ll do another hour of Travis covers.” Then: “This really is our last song ’cos we’ve got to go off and do coke.” Later, he regrets saying anything at all.

Within minutes of coming offstage, Coldplay’s dressing room is mobbed. A bodyguard appears and says Liam wants to see them. He lopes, in looking exactly like he does on TV, and says that hearing Yellow made him want to start writing songs again. And the room fills and fills with fans and celebrities until the only people not in it are Coldplay themselves. Outside in the corridor, they use the same words: “odd”, “weird”, “surreal”. As Chris Martin will say more than once, “It’s been a confusing year.”

Something odd definitely happened on 26 June this year. Travis had just taken the Saturday night Glastonbury headlining slot originally pencilled in for Oasis, much like The Man Who took the millions of sales originally pencilled in for Oasis. Badly Drawn Boy released his debut album, which won widespread acclaim and the Mercury Music Prize. Richard Ashcroft released his solo debut which didn’t. And Coldplay released Yellow.

Beautifully simple, hauntingly happy, Yellow was a perfect soundtrack to the year’s musical spring-clean; out with self-important posturing, in with good tunes and chummy patter. People liked it so much they made Coldplay’s debut album, Parachutes, No 1 and then kept it hovering around the top 10 for the rest of the year.

But with success came the backlash, headed by Alan McGee’s bullying rants about “music for bedwetters”. Others grumbled Coldplay have nothing to say and are nothing more than nth generation Radiohead or Travis trickledown. The criticisms chipped at Coldplay’s confidence. There have been rumours of illness, stress, arguments and members cracking up. Can they cope?

Chris Martin takes an enormous eye-rolling pause from which you fear he may never return. “I feel a bit like we’re human cannonballs,” he finally decides. “We’ve just been fired and while half the time you think, ‘This is great we’re flying through the air’, the other time you think, ‘Shit, when are we going to land?’ People who don’t like you talk about you like you’re the Third Reich. People who do like you will really defend you. So it’s a mixture of extreme excitement and extreme, er, panic.”

A week after the Shepherd’s Bush Empire show, as wind and rain wreak biblical havoc across Britain, Chris Martin sits in a warm pub minutes away from his north London home, a Remembrance Day poppy pinned to his denim jacket 12 days early. Concerned, he gives a woolly hat to a bare-headed Select. Chris Martin is A Good Person.

Conversely, anyone who tries to interview him feels like A Bad Person. After an awkward question he looks around as if searching for an escape hatch, twiddles with his hat, frowns, gives an answer, then immediately retracts it. He is perpetually saucer-eyed, as if everything fills him with either wonder or horror. He has a knack for sharp one-liners but his humour is so understated that it never translates in print. Halfway through the interview he sighs, “Sorry, this is a really shit interview. Do you want to start again?”

You hate talking about yourself, don’t you?

“Yeah, of course. I talk shit.”

Are you more comfortable with it these days?

“No. Less. Less. I hate it. You have two years to make a record and do what you like to it then you have 10 minutes to do an interview that could mess it all up. It’s the Crispian Mills Syndrome.”

Born and brought up in Devon by a teacher mum and accountant dad, Chris is wary of going into detail about his background since McGee et al made it an issue: “What was I like as a kid? The same as I am now, just smaller with a higher voice.” His reticence is understandable given the distorted picture you get from a few oft-repeated facts: boarding school-educated, non-smoking, non-swearing former Christian teetotaler.

He’s only been drunk twice. The first time, he was 17 and kissing a girl at a party, but all he could think of was how he was too pissed to enjoy it. The second time was last year. It was self-punishment after doing something bad to a band member. He remembers lying in Guy and Will’s flat, “dribbling red stuff. I don’t feel like I’m missing out.”

His younger brother is “the anti-Chris, the cool one”, a drum’n’bass DJ who drinks and smokes and has “experienced all these things for me”. The eldest of five children, he has a supportive family.

“I always ring my dad when I want to quit,” he says. “And he goes, [in a plummy voice] ‘Well I wouldn’t give up yet. boy.’ So I think, ‘All right then. I won’t.’ He’d be a brilliant boxing trainer. He sprays me down, rinses out my mouth and tells me to get back in the ring and sock that McGee fella for six.”

Chris says he was a worrier long before Coldplay but fame hasn’t helped. For two or three months after Parachutes hit No 1 the band was a mess. Last time Select met them, at a Portuguese festival (”the most horrible gig we’ve ever played”, says Jonny), they were in a state of minor crisis: exhausted, paranoid, reeling from all the attention. While they were touring, Jonny was reading Das Boot, the classic novel about WWII German submariners losing it in a U-Boat, so the band took to calling their tour bus “Das Bus”. A few days later, Jonny contracted a virus and was out of action for a month. He couldn’t make it to the Mercury awards, where Coldplay were favourites to win. On the night, Chris says, he “felt extremely paranoid. I thought my hair was falling out.”

Why on earth did you think that?

“I dunno,” he frets, rubbing his head. “This year everything’s either amazing or crap. But you have this constant thought, ‘I’m stressed about whether anyone’s liking us but then the world’s destroying itself because of the ozone layer and all that.’ What keeps me going is that I could die tomorrow so I’m always trying to live every day …”

A perfectly timed comic pause.

“… so I just go around saying goodbye to everybody all the time.”

Chris’ cloud/silver-lining dynamic reflects his band’s sound. When Coldplay first appeared they were branded post-Radiohead miserablists. After Yellow, they were dismissed as inanely happy. The truth, and the secret of their appeal, is that the melancholy and optimism are equally powerful.

The anthemic Everything’s Not Lost has gospel’s hard-won uplift – Chris calls it “a chain-gang song”.

“People who write happy songs are often unhappy,” he reasons. “Bill Withers knew every day wasn’t a lovely day. But Everything’s Not Lost is the message of the album. I do exactly what that song does – think everything’s terrible, what’s the point, and then think the point is it’s not that terrible, you’ve got to keep going. The thing is, our lives are great,” he concedes. “We’ve had a funny old time but the four of us are closer than we’ve ever been. Nobody’s going to knock us down.”

Coldplay had their first rehearsal in Jonny’s bedroom on 6 January, 1998. They’d met 15 months earlier in their first week at University College London, but drifted in and out of contact. At first it was just Jonny and Chris, working on a handful of songs. Guy joined the following June, just before dropping out of his engineering course. Finally, Will – a guitarist – was persuaded to give the drums a shot. He blagged them a gig within a week. Their mates packed Camden’s Laurel Tree but Coldplay only had six songs, including Don’t Panic and High Speed. By April, they’d released 500 copies of the Safety EP and they signed to Parlophone a year later, just before their finals. A support slot with Catatonia, the acclaimed The Blue Room EP and the almost-hit Shiver showed promise but nobody, least of all Coldplay themselves, thought they would be 2000’s biggest new band.

This time last year, Coldplay were in Rockfield studios, ready to produce their debut album with engineer Ken Nelson. It wasn’t an easy six months.

“We sweated over it argued over it, went through a lot of unhappiness and pain,” says Chris. “We were reeling from it for quite a bit.”

Even Jonny Buckland, a man who would probably greet news of impending nuclear holocaust with a nonchalant shrug, admits, “The recording sessions were horribly tense. We thought it could be the last record we ever made so we might as well put everything into it. That’s why we got so fraught — no second chances.”

“If you’d spent six months with us in the studio you wouldn’t think we were nice boys,” adds Will. “Fucking fierce rows, big strops, smashing things …”

Does even Chris swear in private then?

“Yeah,” Will chuckles. “Fuck yeah. Absolutely.”

A bunker mentality developed, where the choice between making a song faster or slower became the most important thing in the world. They also insisted nothing would end up on the album unless all four members agreed it was good. “If one member left, we’d split up,” says Chris firmly. “I don’t have any doubt about that.”

On the same May morning Parachutes was completed, Will’s mother died. “I can’t say I had a harsh childhood, but I’ve had a lot of things to deal with, especially in the last year,” he says, pointedly. “People say ‘You haven’t suffered.’ It’s like, ‘Fuck you, you don’t know what I’ve been through’.”

The seductively minimal video for Yellow, with Chris walking alone down a rain-washed beach, came about because it was the day of Will’s mum’s funeral: there was no way the whole band could appear. If you watch it again, knowing what’s in the back of Chris’ mind as he joyously trills along, it puts a lump in your throat.

The following months were difficult. “Jonny was completely laid in bed, Chris was going through mad paranoia and everyone was fucking worried,” Will remembers. “It was just soul destroying. Guy was going mad and Chris was going mad and I was a one-man promotional machine. I think we realised our priorities were all wrong. This is not what we got into a band to do. We’re not orators. That’s why we play music. There’s something inherent in the music that can’t be said, something that exists outside of speech.”

How do Coldplay react to Yellow now?

Jonny: “I try to avoid hearing it. It was on in the background in the Queen Vic the other day while I was watching EastEnders. It was really quiet and I was thinking, ‘I recognise that …’”

Will: “It means a lot because it’s the thing that helped us get there. We were worried people would get sick of it, and I’m sure millions are ’cos it’s everywhere. It’s like, ‘Put a different record on!’”

Guy: “It’s becoming increasingly difficult to get away from. I’ll spend some time off with my parents in Canterbury and turn on the telly and see our video. It can be quite intense.”

Chris: “Somebody rang me up the other day and said Yellow was on a karaoke machine. That made me genuinely excited. It’s got a nice beat.”

Coldplay don’t want to meet Select as a group.

“You come away thinking it’s one loudmouth who doesn’t really know anything and three quiet boys who accept everything he says, which couldn’t be further from the truth,” explains Chris. The people who say less tend to be the wiser.”

If that’s the case, then Jonny Buckland must be Buddha and Solomon rolled into one. Chris claims, “The first person I’d go to with a problem is Jonny, because he’s that sort of person.” Jonny himself says he’s not shy, just happy to be quiet.

Born in London but relocated to north Wales when he was four, Jonny was raised on his dad’s Jimi Hendrix and Eric Clapton records and graduated to his older brother’s My Bloody Valentine and Sonic Youth albums when he was 13, not long after he started playing guitar.

“I’m not technically very good at all,” he concedes with a dry chuckle. “In fact I’m pretty shocking. I’ve got really awful technique but I think Joe Strummer said somebody struggling with their instrument was the best thing to see.”

Are you enjoying success as much as you thought you would?

“More, actually. I thought it’d be depressing.” Then, sounding like he’s found a pound down the back of the sofa, “It’s been the best year of my life.”

Will Champion, too, is starting to find that life in the Band of the Year is good after all. He’s a veritable juggernaut of enthusiasm, raving about fellow Mercury nominees from Leftfield to violinist Joshua Bell and steering the conversation onto the strange joys of Kid A.

“Everyone says Coldplay are doing nothing new and I thought that was fair enough, but then Radiohead come out and it’s like, ‘What are they doing? Where are the guitars?’ For fuck’s sake, you can’t have your cake and eat it.”

Well, at least nobody will say Coldplay sound like Radiohead now.

“Wait till our next album,” he grins. “Child B.”

Southampton boy Will was saturated in a wide variety of music by his teacher parents. He mucked about at primary school and ended up in a rough secondary school. The summer he left, one of the kids that used to bully him was sent down for kicking somebody to death – other classmates are inside for GBH, arson and rape.

“It was quite rough but there was nothing I’d have hated more than public school,” he says. “I’m not so blinkered and, ‘Oh wow, everything’s great, look at my middle-class existence,’ kind of thing. I had to be on my guard a lot more.”

Will radiates a calm reliability, which he worries seems dull. “There’s a fine line between keeping your private life private and coming across as a boring knob-end,” he astutely notes. On the other hand, he’s none too thrilled by fame: “I don’t feel famous at all. I like the way the name of the band is becoming more known but I can put my hat on after a gig and slip into anonymity.”

Guy finds celebrity equally unsettling. He spoke to Liam at the Empire gig just long enough to see if he was how he expected (he was) and said hello to Natalie Imbruglia (whom he quaintly calls “Beth from Neighbours”) but then left: “These are people we’ve never associated ourselves with because they’ve always been ‘famous people’. Now they’re in our dressing room. It was a bit unreal.”

In his teens in Canterbury, when everybody else got into indie, Guy became an obsessive collector of funk and soul: “I’d just buy records by looking at the covers – the bigger the Afro, the better the record.” He has the biggest gap in the band between his personal tastes and the music he plays. And he’s the only one who can talk about the trappings of success without wincing.

“I don’t think anyone’s going to shun these side effects,” he considers. “Ask us in a year’s time when we’re in our country houses, heh heh.”

Eight days after the Shepherd’s Bush gig. Chris Martin is onstage again, this time at the Q Awards. Collecting the award for Best Album, he waves it triumphantly and, in a smart parody of the ongoing Liam/Robbie feud, announces: “Badly Drawn Boy! Twenty pounds of your money. Twenty pounds of our money. Outside!”

Dumbly, the tabloids report this as a vicious war of words. In the past, this would have caused stress, but when Select phones the band on tour in Milan a week later, the mood seems buoyant. Selling out European venues, they’ve been playing their first new songs since Parachutes.

“As soon as we started playing everyone was beaming again,” says Will. “Within a week it went from utter depression to ‘Thank God, we’re back.”

Two of the new songs – In My Place and Animals – have already been aired live. The brooding Animals, in particular, is magnificent.

“Do you like it?” glows Chris. “It’s quite dark but not as dark as some of the other new stuff. I wonder what would happen if we all really got into Joy Division now, ’cos we’ve been getting into the Smiths, and Joy Division’s just the next step downwards into despair. After that it’s Fields of the Nephilim and we’re all going to dress in black.”

Coldplay have a lot of plans for next year. They’re off to America, inspired by Kid A going to No 1, but also want to debut new songs by playing under an alias in tiny venues. Most importantly, they intend to take alternate fortnights off to write the next album and allay the paranoia that they won’t be able to follow Parachutes. They seem happy.

“We’ve had enough stuff fired at us now to either get really aggressive or think, ‘We’re doing alright’,” reflects Chris. “People who buy our record in Dumfries don’t give a shit whether such and such hates us. They just care if they like our record, so we should just care about that too.” His frown uncreases, his eyes widen. “We’re learning to enjoy it.”