Wayne Coyne is sitting in a London restaurant, the debris from a gruelling day's promotion - empty coffee cups, water bottles, a half-eaten sandwich - piling up around him. Such a packed schedule would have pushed a lesser artist to the brink of madness, though if he's had enough he's too polite to show it. Not for nothing is Coyne, 45, known as the most charming man in rock. Unlike most pop stars, he claims to enjoy interviews, regarding them as an invaluable opportunity to spread the word according to The Flaming Lips. And besides, he says, he thinks the people who like his band are "generally pretty cool. What greater compliment is there than getting to meet the people who like your music?"
Part evangelical preacher, part mad scientist, Coyne's boundless enthusiasm about art, life, everything, is contagious. His child-like wonder at the world is reflected by an endearingly upbeat vocabulary that makes liberal use of words such as "Gosh" and "Wow". Coyne tells me about presenting a prize at the Brit Awards. You'd think he'd been offered a trip to the moon.
"I'm always hearing these musicians being cynical about the Brits. Come on, live it up a little. I'm thinking, 'What, you're asking me would I like to go to party and have a good time and rub shoulders with Madonna and Paris Hilton? Of course I would. My wife, Michelle, came with me. We had a ball."
Since 1983, The Flaming Lips - the Oklahoma trio also comprising the bassist Michael Ivins and multi-instrumentalist Steven Drozd - has been sustained by Coyne's febrile imagination and fanatical pursuit of new sounds and ideas. They have survived drug addiction (Drozd used heroin throughout the Nineties), endless line-up changes (Mercury Rev's Jonathan Donahue was once a member) and near penury to become one of the most critically feted rock bands of the era.
Following their last million-selling album, Yoshimi Battles the Pink Robots, Chris Martin, Elijah Wood, Jack White and Justin Timberlake have all proclaimed themselves fans (Timberlake was so smitten after meeting the band that he donned one of their animal costumes and joined them on stage on Top of the Pops).
Now Coyne and co are about to release their 11th LP, At War with the Mystics. The album marks a shift in tone for the band famed for their cosmic lyrical sensibilities and oddball brand of psychedelic rock. Where previous projects have seen them revelling in a fantasy world of Vaseline-smeared toast, all-conquering superheroes, martial arts fighters locked in gladiatorial combat with robots and flying asteroids, here their concerns are somewhat closer to home.
For the first time, politics has crept into the band's lyrics. "With what's going on in the world, and with Bush and his band of buffoons in charge of our country, you could say that we're working through some frustration and anger," says Coyne with customary cheeriness. "We're not saying 'Let's all go kill George Bush,' or anything. We would never make protest music, and I don't necessarily think that music can change the world. I mean, it's wonderful but music is just music. But the idea of ignoring Bush and this war is ridiculous too. It's like when you're so mad, you punch the wall. Obviously it doesn't do you any good, but if you don't punch the wall, you feel even worse."
I note that, for all their escapist whimsy, The Flaming Lips' songs have always had a dark undertow. "Do You Realise?", the Spectoresque single from their last album used for a series of Mitsibushi TV ads, came with a stark view of life and death: "Do you realise that you have the most beautiful face? Do you realise that everyone you know some day will die?"
"Sure," nods Coyne, "I think in our earlier stuff we sang about life being hard and unpredictable and we would always speak of this existential uncertainty and despair. But I don't think we really knew. As you get older you really do have true experiences with life and death. You don't look to the universe for any answers any more. The only answer is your own experience and the experiences of those around you."
Death has loomed large in Coyne's life in recent years. He lost his father to cancer in 1997 while his mother died in 2004 during the recording of the new album. "Of course, it was devastating but I think when we were making and touring the last record I could look at my mother and know that she was not going to live for ever," he reflects. "The experience of losing someone changes you more than any book you could read or movie you could watch. But it's not a case of the grass was green and it's now grey. The sunsets are still beautiful.
"The day my mother died Michelle and I watched the sunset, not because it was poignant but because we looked over and it was there. It was hard but my mother's death didn't take everything good out of our lives. As these things happen I will stand up again and say the world is wonderful. Just 10 years ago people could have looked at me and said, 'What do you know? You've got this great life, you're in a rock band and you can do what you want.' But now I can say 'Hey, I know stuff.' If anything, we've accepted that there's limits of optimism and that there's some value in hopelessness. In my mind, all that makes for a more enriched life."
In professional terms The Flaming Lips have had their hard times, too. The band spent their first decade trawling the US college circuit, playing to small and largely unmoved audiences. So muted was the reaction to their early shows that Coyne frequently thought of throwing in the towel and resuming his career dispensing fast food. It wasn't until 1991 that they signed to a major label though, with their outlandish musical output, they seemed destined to remain on the fringes of American alt.rock. Aside from an unexpected US hit in 1993 "She Don't Use Jelly", about a woman who breakfasts on Vaseline, they didn't' trouble the charts.
But then came 1999's The Soft Bulletin, a spectacular album hailed as a modern psychedelic masterpiece that elevated The Flaming Lips from impoverished outsiders to financially viable indie heroes. Their follow-up, 2002's Yoshimi Battles The Pink Robots, was an even bigger hit and was hailed by some more excitable critics as comparable with Sgt Pepper and Pet Sounds.
Now, it seems, the Lips are on a roll. Coyne is considered starry enough to appear at the Brits, while "The Yeah Yeah Yeah Song", the first single to be taken from At War with the Mystics, is expected by the band's record company to sail into the top 10. Yet Coyne insists there's been no master-plan to make them appeal to the masses.
"In my mind we are still legitimately weird and I've never thought of our music as having any commercial potential," he says. "I would say everything that's happened has taken place little by little. But it's not like we always wanted to be weirdos. We want to sell records and have people come to our shows. Here I am talking to you because I want you to go out and tell people about our record.
"I think the whole process of making music has become much easier. With iPods and computers, there's so much more access to it these days. If you want a record you don't have to wait for the store down the street to order it for you. You can just listen to it there and then.
"And music's changed too. In the UK especially, people are a lot less mainstream in their tastes. I like to think that if you heard us for the first time now, you wouldn't be too freaked out. You might think to yourself, 'Well, that guy doesn't sing very well,' but otherwise you'd probably go with it."
The Lips' legendary live shows have also been crucial to their success. A firm believer in the value of entertainment, over the years Coyne has hatched a series of hare-brained plots to win over audiences. Performances have been known to take in glove puppets, animal costumes, buckets of fake blood, confetti, glitterballs, gongs and Coyne rolling across the crowd in a giant plastic space bubble.
Not all the schemes have come off quite as planned, however. In 1997 he came up with the "Parking Lot Experiment", in which he wired up 50 car stereos in an underground car park in order to create a single piece of music. You had to admire his ambition, though the result was at best chaotic.
The following year's "Boom Box Experiment" saw him orchestrating a sea of customised cassette recorders containing prerecorded Flaming Lips tracks, yielding a four-CD album that was designed to be played simultaneously. Needless to say, those with fewer than four CD players in their homes remained ignorant of its charms.
Coyne blithely admits that, as a result of his stage antics, most people tend to assume he's either crazy or on drugs. The band's former manager Michele Vlasimsky once remarked: "These are not normal guys from normal families - you're talking about freaks."
However, an hour spent in Coyne's company reveals him to be apparently sound of mind. And contrary to popular belief, he hasn't taken LSD since his teens. "I'm always having to convince people that I do normal stuff like washing dishes and cleaning the gutters, and I'm not permanently off my head. The desire to roll around in a space bubble is just one side of my personality. And wouldn't most people do it if they had the chance? The difference is that I really do have the chance. Ain't that great?"
Asked if he ever feels pressure to up the ante with each new show, he replies: "Not at all. This isn't me trying to be flamboyant or outrageous. I genuinely love all that stuff. The best things that we've ever done we've just stumbled along by dumb luck, like using glove puppets and animal costumes. Anyone could have done it really. It's not big or expensive.
"When we first did the space bubble, it was like 'Well, Thom Yorke's not going to get in one of these things, so I might as well.' I figured that if I didn't break my neck it would probably be pretty cool. It would be all wrong if we didn't do it. I just use my experience of seeing The Who and Kiss when I was a teenager. If Kiss didn't do the fire and the make-up, I'd have said, 'Hey, I want my money back."
For the endlessly energetic Coyne, the novelty of being in a successful band is showing no signs of wearing off.
"I mean, come on," he says. "This has got to be the coolest job in the world. It's all about opportunities and what you do with them. I see other bands and they've got all this money and all this attention, they've got this audience waiting to love them and all they want to do is complain.
"The difference with us is that we can see how great it is. Right now, we've got people giving us tons of money to make records and all these people coming to our shows. I see our job now as stretching ourselves even further, doing new things and continuing to earn that devotion. It doesn't get any better than that."
The album 'At War with the Mystics' (Warners) is released on 3 April. The single 'The Yeah Yeah Yeah Song' is out on 17 April. The Flaming Lips play the Albert Hall on 22 AprilReuse content