Age has not mellowed him, this beacon of cool eccentricity in a world of manufactured music. We discover what makes Jarvis Cocker carry on.

The Wolseley, on Piccadilly, at teatime is a verdant and exotic social habitat. In the middle of the room, Stephen Daldry is sitting next to Nancy Dell'Olio. It could be Baz Luhrmann's casting for a musical remake of Separate Tables. I'm early, waiting for Jarvis Cocker, cock-a-hoop, cock-a-snoop Cocker. Cocker who deflated Michael Jackson and the vaunting, inflated, precious self-importance of international pop megastardom. Cocker who formed the one Britpop band that managed to get through the Cool Britannia years without becoming a self-parody or disappearing up its own winking irony.

Everyone I told I was going to meet him said the same thing: "Oh I love him." When I asked why, they all said: "Because he's so clever." To be able to project cleverness through pop music is in itself proof of unusual cleverness. And to be loved for being clever is exceedingly rare.

Alan Samson, a middle-aged publisher whose brows are so high they almost count as a mansard head extension, told me that once, returning from a Frankfurt book fair, he'd come upon Jarvis going round and round the luggage carousel. The great and the good of British letters watched as he slowly went past them. "He wasn't doing anything, he didn't look drunk. He was just being a suitcase. It was" - Samson fished for the mot juste - "it was a real Carry on Cocker. I've adored him slavishly ever since." What sort of suitcase would Jarvis Cocker be? A Louis Vuitton steamer trunk? No, too Puff Daddy, Shirley Bassey. A wheelie Samsonite with a telescopic handle? No that's Robbie Williams. A Gladstone bag? Bob Geldof. And then here he is, standing in front of me - an elegant golf bag with a novelty lemur driver sock sticking out the top.

Pop stars spend years trying to hone a look, a bespoke image. They have armies of stylists and designers dyeing, stitching and painting them into some sort of moreish memorability, then here's Jarvis: the most instantly recognisable, utterly original geek chic, spot on the geist. And you just know that a thousand stylists working for a thousand years couldn't have come up with a single inch of him. Nobody looking like Jarvis is going to get past the Sheffield heat of The X Factor. He is the antonym of the manufactured, cynical, second-guessing, packaged pop band, and he represents everything that has always been eccentric, brilliant and transcendent about home-grown music. It's a decade and a half since Pulp jittered and flittered into the public ear, and he still looks authentic in an excellent tweed jacket, which fits somewhere between Bryan Ferry and Norman Wisdom, and an exceptionally thin classic Cartier watch.

The oversized owlish spectacles? Where do they come from? Cutler and Gross. Which is, by coincidence, where my black-rimmed spectacles come from. We share myopia. Jarvis is having a bad hair day. It's just been washed, so it has ideas above its station. It's Bee Gees wannabe hair.

Jarvis doesn't really play an instrument. He's planning on learning the piano, and can thrum a guitar, but he's not Jimi Hendrix or Liberace - and then there's that voice. Memorable, but not exactly Paul Robeson or Aled Jones. It's not a sound that pricks the eye or elevates the short hairs with its sonorous tintinnabulation. It rather raises the question: why did he ever become a pop singer? "Well," he says, as if it's the first time he's ever been asked, "I suppose it was because I was shy. I find it quite difficult to talk to people." Right. so you thought, because I feel self-conscious meeting people, what I should do is stand on stage in spectacles and sing at them in a frankly home-made voice? "Yeah. You don't have to talk to people or chat them up or be charming if you are in a band. You're just in a band."

The point was, and is, that it's not how Jarvis sings and plays or dances or looks or goes round carousels, it's what he sings. He is that increasingly rare thing, a songwriter whose words mean stuff and matter. They aren't simply random noises from a rhyming dictionary. But why still do it? As a listener, there comes a point when you grow out of music. It stops being the soundtrack of your life. Surely that must also be true for performers. Isn't there a point where you say this isn't a job for a grown-up, unless it's just vanity, greed or therapy? And you become the Rolling Stones or Reg Presley, trundling the Troggs around student unions banging out Wild Thing twice, with an encore of Wild Thing.

"I don't think that's necessarily the alternative, but it is true that pop music is self-obsessed. Both the making and the listening. It's about me, me, me in an egocentric, self-indulgent way, and you do grow out of that. Though I think my generation want to go on listening to their music and to songs that have a message, have a point."

Of course, it is particularly singer-songwriters who get to go on, like Morrissey, I say, and we both roll our eyes. Or Leonard Cohen, he offers. I can't bear Leonard Cohen. The girls who wanted to talk all night and never do anything listened to Leonard Cohen and read Sylvia Plath.

"Okay, you need to get over your bad experience with Leonard Cohen. What did the girls who did do stuff listen to?" James Taylor, and they read Muriel Spark. "What you want to avoid," he says, "is the grandiose concept album of middle age, with a philharmonic orchestra or a Macca oratorio or, worst of all, a rock opera like the defining ghastliness of the Who's Tommy."

I see men of my age in record shops buying "best of" CDs of all the stuff we bought when we were kids. "That's just what I've been doing," says Jarvis, and out of an HMV bag he pulls a four-CD Jake Thackray box set. Jake Thackray! When was the last time you heard or thought of the Eeyore of folk singers with the nutty, slack voice? That's so beyond left-field, so radically out there, it is sort of inspired. Go and download Jake Thackray now - relive, or discover, Lah-Di-Dah. It's brilliant.

What does Jarvis read? "I tend to get obsessed by one writer and read everything they wrote," he says. "I've just done all of Carson McCullers and a couple of biographies. There's a sample of her voice on my new album."

I've had the record on continuous play for a couple of days, and there's precious little evidence in it that age has mellowed Jarvis or plumped his prose into easier listening. Don't Let Him Waste Your Time is the repeatable, memorable hit. I particularly like Fat Children, with the refrain "Fat children took my life". And right at the end, after 20 minutes of silence when you think it's all over, there's a stealth track called Running The World that doesn't register on the iTunes radar, with the blissfully Cockerish lines: "It's anthropologically unjust / But the takings are up by a third / So cunts are still running the world / ... Fuck the morals, does it make any money?" I love Running The World because it proves I'm not so grown-up that I can't still be impressed by expressive profanity and adolescent subversion.

Stephen Daldry comes to say hello, and with a flustered social dyslexia, I introduce him as Roger Daltrey. "That wasn't Roger Daltrey," says Jarvis. No, it was Billy Elliot. "I thought I'd hate that. but I really loved it," he says.

Jarvis grew up in Sheffield and has a characteristically South Yorkshire deadpan delivery. So you're never quite sure if he's being ironic or dead serious. What was the last joke that made you laugh, I ask. "I was watching kids' TV with my son, and they said, 'Why did the baker smell? Because he needed a poo.' It made him laugh, and I thought that was quite extreme for a toddler." Yes, scatology is unnecessary. "No," says Jarvis, "it's that the kid understood the pun in 'needed'."

What's it like having to do Common People now, I ask. It's such a colossal bit of rock heritage. Do you resent it, mind having to play it? "We used to jazz it up just to keep it fresh, but the audience really hated that," he says. "You've got to do it exactly like the record. It's their song, not mine, and actually it's not a track you can just coast through. It's quite emotional. Starts off quiet and gets pretty angry. You can't fake it." It's a brilliant brilliant song, I say. Jarvis looks pained behind the glazing: "Sorry, I don't take compliments well." So I change the subject. Did you see Pink Floyd on Band Aid? They sounded exactly like on The Dark Side of the Moon. It was uncanny. "Yeah, I thought the old groups were much better than the new ones on that.£

"You don't think there's a working class any more," he continues. "I read your book, now I think we're all middle class. You know, what the market and capitalism has done is, they've taken workers and they've made them consumers, users." Pulp never got involved in the New Labour cocktails-at-No-10 love-in thing. "I was pleased Labour won, though. I tried to vote in the last election, but I wasn't on the electoral register. In the end, it was a bit of a relief that I couldn't vote for Blair again. I'm not going to vote Tory."

He takes a scone and puts on cream, then jam. It's the final evocation of cool and utter rightness - and it could so easily have gone the other way. Jam then cream, a dainty disaster. He eats ruminatively; he's late for the photographer, has a hair moment and fixes me with a glazed look. "Just make it up, honestly, make me sound interesting. My favourite film, by the way. is Top Gun." And with that he got up, grabbed a microphone from the bar, sashayed across the crowded room and sang You've Lost That Lovin' Feelin' to a simpering Nancy Dell'Olio.