It's the early hours of a Thursday morning and Bush singer Gavin Rossdale is sat upfront of a tour bus currently hurtling down a rain-swept motorway from Nottingham to London. The band are two dates into a European tour in support of their new album 'Golden State' and Kerrang! has managed to blag some quality fly-on-the-wall time with Rossdale.

The singer has spent the past hour sharing his thoughts on life, the universe and Bush's role in that ever-grand scheme of things. It's hard to imagine that the man who mere hours earlier was projecting nuclear-glow rock star energy in front of a heaving Rock City and crowd-surfing with the wild abandon of someone half his age, is the same gently-spoken person sat here, giggling at the fact that right now he's also incredibly stoned thanks to the effects of the magnificently pungent joint he's enjoying.

"We're a couple of potheads," he grins, motioning to tour keyboardist Sacha sat beside him, frantically rolling up before losing yet another train of thought.

This is not how you expect it to be. In America, where Bush have consistently shifted units in their millions, Rossdale is an A-list celebrity (and one with a particularly nice set of cheekbones at that) and should therefore be an exercise in unapproachability and affectation. Instead you get an engaging, near-stream of consciousness that enthuses about the likes of PJ Harvey, At The Drive-In and Leonard Cohen ("Not a Kerrang! thing I know, but if you've ever cared about lyrics..."); about having his wallet nicked while crowd-surfing in Brazil; about Tool bassist Justin Chancellor ("Probably the best musician I've ever seen live"); or having The Jesus Lizard on tour ("I loved every second seeing that band onstage"); even his plans for Christmas (to be spent with his dad, incidentally) in a quietly spaced-out manner. So unassuming it's ridiculous.

You would expect at least some display of attitude - particularly after eight years of being ignored in his own country - but there is none. In fact he's still excited about touring a new album here.

"Playing live is everything," he says. "And I love fdoing this more than ever."

'Golden State' is far more straightforward outing than it's predecessor, 1999's more experimental 'The Science of Things' - the least well-received of Bush's four albums by both the public and the rest of the band. Its creator describes the new record as "well balanced". Only two tracks - the textured, ambient 'Inflatable' and 'Out Of This World' - could have conceivably slotted into 'Science...'. Coincidentally, the formaer is Gavin's favourite song on the new album.

"See, I could do a whole record of stuff like that," he sighs. "But I'm lucky if I get two 'mellow' songs per record. Rock songs involve the rest of the band completely."\

Ah, the rest of the band. Earlier this year, a K! cover feature saw the singer offering conflicting versions of life in Bush - one where he claimed everything was rosy in the Bush camp, the other where he claimed that his dreams of expanding Bush's musical horizons were being held back by a band wanting to stick to the same rock formula. Since the ice has been broken and since there are several hours of travelling ahead it only seems fair to ask: will the real Gavin Rossdale please stand up?

"I got really busted in the cover story," he laughs. "If I was affected by all the stuff that's been said over the last eight years I wouldn't be on this bus now."

Yes, but are you or are you not getting on with your band?

"This band is like a family," he says. "Sometimes you just want to fucking throw someone out the window - just nudge them out and not tell anyone they fell out the bus." He leans conspiratorially. "But that's okay. Because you have to appreciate that they're thinking the same thing about you."

Right now however, no-one is about to find themselves thrown from a window. As Gavin heads downstairs, after apologising profusely for "rambling on and on", it transpires there's a far more important activity taking place in the lower lounge: namely an arse wiggling contest to a Prince 'greatest hits' compilation.

For a band who have sold some 11 million records and probably have bank accounts to match, Bush are a pretty unaffected bunch. Twelve hours earlier, on the day of the Nottingham show, drummer Robin Goodridge, guitarist Nigel Pulsford and bassist Dave Parsons are killing time in and around Rock City beofre soundcheck (Rossdale is still missing in action in Glasgow, the scene of the previous night's gig). It certainly doesn't feel like you're in the presence of one of the most successful UK rock acts of the last decade. There are no officious tour managers (in fact there isn't even any tour manager today), no obstructive bodyguards or entourages and no mistreatment of the support act.

"There's just no need for that stuff," says Robin Goodridge, reclining in the band's tour bus.

If Gavin is the sensitive spirit of Bush, then Goodridge is definitely the band 'geezer' - loud, confident and very talkative. Declaring the rawer rock energy of 'Golden State' to be more his "thing", the drummer says he's enjoying the tour. So long as you don't refer to it as such.

"This isn't a tour", he says with near-incredulity when asked how these dates compare to the much bigger operations in the States. "Touring is about isolation. This is easy. I left my house yesterday, flew to Glasgow for a show, I'm going home tonight, we play London tomorrow. It's like a job. I'm going home most nights!"

He should know a thing or two about touring in any case. Given that they always enjoyed far greater success in the US than their home country, it's likely that Bush have canvassed the States more thoroughly and more intesely than any other UK band you'd care to mention. Year-long treks across America? Now those were tours.

"Shame I can't remember any of it," he adds with a smirk.

Supporting Bush on these dates are new UK signings to Ross Robinson's I Am label, Vex Red, personally invited on the jaunt - at no 'buy-on' cost, it has to be said - by the headliners. It's heartening to see a big British band giving a smaller one a leg-up. Robin notes that one of "God's great gifts" to Bush was not to have to be the support act on any big tours.

"We're always really cool to our support bands," he says. "I've been in support bands before Bush where we've been treated really badly. So I vowed that if ever the shoe was on the other foot I'd be cool."

Back inside the venue shoundcheck is underway. Vex Red sit by their gear waiting their turn, killing time by attempting ambitious weaves inand out of an obstacle course of equipment cases, with varied results. On learning the press are in their midst, they beg to be interviewed so they can be asked "just one more time" about Ross Robinson and why they "don't sound like Slipnot".

"There's always tension," says Nigel Pulsford on the subject of band relations. The guitarist is sat with basist Dave Parsons in the downstairs lounge of the bus. Pulsford is the perfect foil for the more dreamy Rossdale; he's got a dry sense of humour that could be mistaken for general grouchiness, were it not saved by an avuncular smile and the occasional rasied eyebrow. Of course, that doesn't mean he isn't adverse to leading his band through a mock sing-song at a piano for benefit of the cameras, as he will do in 24 hours' time in London.

"Recording 'The Science of Things' was a bad time for us," he continues. "But you have to have opposing visions when you're making a record, otherwise you lose all the 'spikes' that make it interesting and you just end with something wanked around in the studio that's one person's idea."

Unsurprisingly, considering how much its predecessor was seen as 'Gavin Rossdale's record', Nigel Pulsford and Dave Parsons are much happier with 'Golden State'. Equally unsurprising is their relief that Ross Robinson didn't end up at the controls.

"Gavin was keen," shrugs Pulsford. "I wasn't."

Robinson is known to employ rather unorthodox methods to bring out the performance inhis charges - verbal abuse, physical abuse...

"I could see Ross getting punched out a lot if he recorded with us," snorts the guitarist in reply. "I remember seeing him at the Kerrang! Awards a couple of years ago. He was with Slipnot who were being really 'naughty' and setting fires to tables and stuff. Then he got up to collect an award and they all stood up and applauded like fucking boy scouts. Hilarious".

Dave and Nigel are both master of the understatement. They're friendly enough, but you do keep expecting them to say "don't be so ridiculous" at any moment. It says something that inthe space of eight years, playing hundreds of shows, with hundreds of different bands, the pair find it hard to come up with any highlights. Or even lowlights (after a bit of prodding, Nigel declares Everclear to be "fucking wankers of the highest order"). This is not Motley Crue. In fact it's struggling to be Westlife. Even the band suggest I'm better off interviewing their guitar tech Dale - a man who actually learned his trade witht he Crue, and who now has to keep being reminded by his current employers that "It's not the 80s anymore". Unfortunately Dale is busy.

"We've never been that sort of band," sighs Nigel. "It was weird when we first went out to the States, because we thought all that 80s stuff had stopped, but it's still really rampant - and with supposedly cred bands too."

Dave Parsons explains his reticence to revive tour anecdotes because he doesn't want to sound liek a "flash git". The thing is, Bush have played some pretty flash gigs in their career. Like the time they plated to 350,000 people in Denver, or their Friday night headline slot above Korn at 1999's Woodstock III festival - a gig Dave hilariously describes as "alright". Something the bassist is looking foward to, however, is tomorrow night's London show at Brixton Academy.

"We've played some great places," he says. "But to get to play Brixton Academy, which is where I saw the Clash years ago - and one of the best gigs I've seen. That's brilliant."

Brixton Academy is the biggest venue Bush have headlines in this country. It might pale in comparison to the sheds and enormodomes of America, but the 4,500-capacity South London venue still represents a significant moment in the band's career - not least as a raised middle finger to everyone who's lobbed barbs and brickbats at them over the years.

Tonight, Bush rise to the occasion in style. However much Gavin might love the mellower moments and however much the rest of his band might love to just rock, the foursome are stunning, producing the kind of energy that you rarely find nearly a decade into the career of a very successful rock band used to playing far larger venues thanthis across the other side of the Atlantic.

And Gavin Rossdale is the star of the show. There might be a great many bands out their heavier than Bush, but few frontmen give quite as much as Rossdale. Watching him burn livewire intesity from the stage, soaked in sweat and throwing himself with utter conviction into songs he's sung countless times, you realise why he's the focal point of the band, and it's not simply because he's the one out front either. As 'Swallow' [sic] comes to a cataclysmic song-along close, he stands on a monitor, arms aloft, radiating excitement that just can't be faked, and for one moment Brixton Academy feels 10 times bigger.

After the gig, Gavin Rossdale looks elated.

"I was filled with so much joy from the crowd that I was thinking, 'Surely I'm not meant to be this happy?'," he says slowly. "It was the weirdest dilemma.

He ponders this for a moment.

"Because I'm still a million miles from thinking I'm any good."

Rest assured he just got a little bit closer.