To the Royal Opera House in London’s paparazzi-strewn Covent Garden for the GQ Man of the Year Awards. It’s a celebrity menagerie: Boris Johnson, Gordon Ramsay and Josh Brolin, James Nesbitt and Kirsty Gallagher, the three surviving members of Led Zeppelin, two of the standing members of Primal Scream, a cloud of comedians (Steve Coogan, the Mighty Boosh, the actor-writers of Gavin and Stacey), a wobble of models (Elle Macpherson, Daisy Lowe). There’s Lily Allen, one of the award ceremony’s hosts. There’s Elton John, the other one. Oh, who will drink whom under the table? (Probably Lily Allen. As usual.)

Sitting near the back are Keane. They’re the only performers tonight, opening proceedings with a bash through their recent free single Spiralling (half a million copies were downloaded during the week-long promotion). A few minutes before the festivities commence, the three bandmates are nervously tapping feet, fingers and crockery, and fending off the blandishments of waves of waiting staff. Drummer Richard Hughes, 32, forgoes the proffered dinner; he doesn’t like to play on a full stomach. Pianist and songwriter Tim Rice-Oxley, 32, hovers sideways in his seat, ready for action. Singer Tom Chaplin, 29, seems especially jittery; no, he won’t have a nerve-steadying drink, thanks very much.

It’s a big night for Keane, in more ways than one. It marks the first public performance of a song from their imminent third album, Perfect Symmetry – an album that, for a while, looked like it might not get made. And it marks the return – the revival if you like – of Chaplin. He was supposed to attend this awards ceremony two years ago, to collect the trophy for Band of the Year: the trio of public-school pals from Sussex were riding high on the eight million sales of their 2004 debut, Hopes and Fears, and 2006’s follow-up, Under the Iron Sea. But in September 2006, Tom Chaplin was in rehab at the Priory, being treated for addiction to alcohol and cocaine. Rice-Oxley and Hughes had to pick up the hefty glass bauble without him.

If you ask Chaplin about 2006 and when he realised his partying was getting out of control, his normal bluff heartiness stutters to a halt. “Phewwwww,” he says, exhaling heavily. “I don’t know. It started with isolated things. It’d get better for a while, then other things would come along and I’d make mistakes. We’re not talking an Amy Winehouse/Pete Doherty scale of not turning up to stuff, but there were certainly things I missed.”

Keane had become very big very quickly. Early singles Somewhere Only We Know and Everybody’s Changing were huge hits. Like their friends and peers Coldplay, Keane knew their way round a piano ballad that touched a universal chord: sensitive, uplifting, singalong. Hopes and Fears entered the album charts at No 1 and won the band two Brit Awards. In the UK in 2004, only Scissor Sisters sold more albums than Keane.

The rest of the world was almost as enamoured of the three polite young men from Sussex. Second album Under the Iron Sea followed hard on the heels of a world tour. The mood was darker but the songs – Is It Any Wonder?, A Bad Dream – were just as catchy.

In large part, this was down to the ringing voice and personable appeal of Chaplin. Here was a chubby, cherub-faced chap who seemed barely out of short trousers. An unlikely pop star, but an appealing one. A safe one, even.

It was, therefore, something of a shock when Chaplin was revealed as a boozehound and cocaine addict. He was the unlikeliest rock’n’roll party animal. But his problems were very real indeed.

“What really was a wake-up call for me was that I just wasn’t very happy. I felt very, very miserable. I’m a manic person. But that element of being wired up all wrong, it’s part of what makes you want to be the frontman of a band.” This is why, he reasons, a lot of singers end up in “that situation” of drug abuse, breakdown and, if they’re lucky/strong/supported, recovery.

The day before the GQ event I meet Tim Rice-Oxley for breakfast in a pub near his home in Bermondsey, South London. Our appointment is at the very proper-job time of 9am, and he has the muesli with fruit. The pre-interview talk is of kitchen knives, foodie paradise Borough Market and his attempts to make sashimi.

Rice-Oxley is not like most young, multimillion-selling rock stars. He’s polite, friendly, but also upper-middle-class clenched, talking passionately but somehow drily about the nuances of the new record. The son of two doctors, he’s well-spoken – like Chaplin and Hughes, he attended Vinehall prep school in Sussex and boarded at Tonbridge in Kent. He read Classics at University College London, and admits that Ovid’s poem Pygmalion influenced the lyrics of Spiralling. He writes all of Keane’s songs but has no interest in singing them. Indeed, he visibly shudders at the very thought. Chaplin, whom he’s known almost his entire life (their mums are very good friends), is much better at that job. And nor is it simply a case of the singer being a mouthpiece for the songwriter. “Tom’s brilliant at adding little flourishes. It’s those little things that lift a song into something much more beautiful.

“The relationship between the two of us and the song is unique,” Rice-Oxley continues, citing their “20 years of making music together… I don’t imagine that any other band of our age would have that.”

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