At the age of seven, Jarvis Cocker realised he was not immortal. Now the Pied Piper of his generation has decided the end is nigh.

He doesn't own a house ("property is theft"). He is only just coming around to the idea of getting a new car to replace his beloved Hillman Imp ("I've hung on to it because it reminds me of my former existence, but when it broke down in the fast lane of the A40 I thought, "I don't want to be found a bloody mess inside the wrecked remains of a Hillman Imp."'). And his most spectacular indulgence since the money started rolling in was to pay £2,000 at Bonhams auction house for a complete set (1965-76) of the women's magazine Nova. lt's true what they say: there's only one Jarvis Cocker.

In case anyone out there is wondering, he wanted the magazines "for the look and the graphic style" which he happily admits to having plundered for the artwork on Pulp's last album Different Class. Did he have to go through an ugly bidding war to get them? "I did actually. My rival was a man I vaguely recognised, and it became a really macho thing in the end. Whoever didn't get the women's magazines was going to leave that room never able to get an erection again."

It's only on hearing the familiar measured South Yorkshire tones of his speaking voice that you realise how long Jarvis Cocker has been away. Then he sits forward in his chair, exchanges his plain glass photo-session spectacles for the ones with the real lenses in, and passes on the accumulated wisdom of 15 months spent as near to out-of-the-limelight as it was possible for him to get. "You wake up in the middle of the night," he observes, in that seductive half-whisper which gives pause to protective fathers and doubting husbands from Troon to Aberystwyth, "and you suddenly start to think about getting old."

This is not the way global pop icons normally announce their return to the fray, but Jarvis Cocker didn't get where he is today by being one of the crowd. In his particular field of employ there are two approved approaches to advancing age. (Jarvis was 34 last birthday, which is hardly ancient by any sensible reckoning, but pop years are a bit like dog years.) You can either make frantic, Canute-style attempts to stem the tide, or seek solace in a spurious ideal of maturity. You can get your hair cut, go on tour again, and exchange your wife for a younger model or lose your spark, record an Unplugged set, and hang on for that guest slot on Masterchef. It's not much of a choice.

The new Pulp single, their first new recording since Jarvis's symbolic bottom-waggling dethroned self-styled King of Pop Michael Jackson at the 1996 Brit Awards, has no truck with such dubious defence mechanisms. Help The Aged looks Father Time full in the face and tips him a cheeky wink. 'Help the aged.' Jarvis croons, 'one day they were just like you - drinking, smoking cigs and sniffing glue...' This is not, as it initially seems, a scandalous assault on the moral integrity of a greying populace, but a wake-up call to youth-fixated Blairite Britain. Behind the facial lines of their elders, Jarvis counsels his callow constituency, 'You may see where you are heading, and it's such a lonely place.'

The inevitability of the ageing process has not exactly been a staple of the singles charts over the years, but for those who don't feel like addressing this issue right now, leaving the country is probably the only option. Because Jarvis Cocker has raised the stakes. When homegrown pop music was supposedly dying on its backside relegated from unifying national indulgence to the unhappy preserve of a dwindling rump of cranks and obsessives - Cocker, along with the Gallagher brothers, Take That, Blur and the Spice Girls, picked it up by the scruff of the neck and put it back at the centre of Britain's cultural life. Others might have flicked more V-signs at photographers or shown greater expanses of skin, but no one else did as much as Jarvis Cocker to overturn the assumption that pop's biggest and best moments were all behind it.

From getting every question right in the quickfire round of Pop Quiz in July 1994 (it doesn't sound like much, I know, but from such tiny acorns, large oak legends grow), to Pulp's triumphant headlining appearance at Glastonbury in 1995, Jarvis the pipe-cleaner Pied Piper seemed to be on a mission to prove that pop's present and future could be more than just a brash virtual echo of its past.

Half the fun of watching Pulp before they made it big was the way that Jarvis would ramble on between songs, seemingly oblivious to the indifference of the assembled multitude. Then, suddenly, it seemed as if he could say almost anything he liked and people would hang on his every word. It must be a bit of a responsibility - knowing that if you speak, everyone will listen. "It is," Jarvis admits blithely, "because I talk a right load of rubbish most of the time. It's daft really, you start off in a group because you want people to notice you and listen to your take on the world - the whole thing is very egotistical - then things go well for you and you have to spend all your time emphasising the fact that your opinion is no more valid than anybody else's."

Sitting in the recreation room of the west London recording studio which has been Pulp's home from home for the past 10 months or so, Jarvis turns off MTV because he finds it distracting. Whatever else Help The Aged does, it seems sure to leave a sizeable crater in the contemporary pop landscape. Not only on account of its heavyweight subject matter which its author sums up as "Thinking about what people of our generation are going to be like when they get old" - but also because the music has the stately but unstoppable momentum of a runaway traction engine. With its swirls and its squeals and its general air of barely suppressed hysteria, Help The Aged seems a very dramatic kind of statement to come back with. "It should be dramatic," Jarvis insists, "because the encroachment of death into life is a dramatic thing."

This is not one of those embarrassing moments when a pop star suddenly realises something everyone else knew already and then makes a huge song and dance about it. Jarvis first became aware of his own mortality at the age of seven (coincidentally or otherwise, this was the year Cocker senior walked out on his family, leaving his only son to be raised in the company of women). He was playing outside in his Sheffield back yard and had just jumped over a wall when the whole thing became clear to him. "It was a really upsetting experience," he remembers, "to think that you were going to be here for a certain amount of time and then not be here."

Were such moments of lucidity a common feature of his formative years? "You do play little games with yourself. I remember getting on a bus and thinking, 'Will I remember this moment for the rest of my life?'" He pauses, his comic timing as unerring as ever, "and I have done, but only because I wondered whether I would do or not." On the face of it there's no obvious reason for Jarvis's thoughts to have turned back to mortality at this precise moment. The usual vindictive rumour-mongering which accompanies any absence from the public eye is confounded by his chipper demeanour: if Jarvis is really addicted to a deadly cocktail of laudanum and Alcopops, he looks remarkably well on it.

But while other people's pasts catch up with their present, Jarvis Cocker's present has been catching up with his past. He has always been an unapologetically autobiographical songwriter, and given that the recordings that first made Pulp's name in 1992-4 were mostly about his Sheffield adolescence, and their 1995 album Different Class dealt with the simmering feelings of class resentment that accompanied his later move to London, the obvious subject matter for the next recording would be the business of celebrity - something Jarvis has admitted on many occasions to having "absolutely no interest" in writing about.

Rich and famous as he is, he can't go on about the common people without falling into the same voyeuristic mindset that his own songs have criticised so eloquently in the past. Perhaps the Grim Reaper points a way back into the universality that is his natural habitat. "Or maybe," Jarvis suggests helpfully, "I started thinking about all this stuff because in a way I've achieved what I wanted to achieve. And when you've done that, you do begin to wonder if you should just get out of the way and let someone else have a go." Watching the Rolling Stones creak into gear again must be a salutary lesson for the maturing popster. Jarvis is sympathetic: "If the choice is sitting at home on your own or being on a stage with everyone clapping and saying you're great, you can't blame people for choosing the 'you're great' option, but for me there's got to be more of a reason than that to carry on doing it."

Accordingly, just before last Christmas, he "sat down and had a good long think" about whether he had anything more to say, and decided that he did. It might seem odd that he should consider retiring after just a few short years at the top, but Pulp's history is like an iceberg: only a small portion is visible above the surface of the limelight. First conceived in the mind of the teenage Cocker before Margaret Thatcher came to power, Pulp spent a decade-and-a-half in fairly unremitting obscurity - Jarvis performing in a wheelchair and band members being seduced away by the lure of charismatic Christianity - before things finally started to go right.

In retrospect, Jarvis seems to have been destined for stardom. What other option could there be for someone whose mother (who was, and judging by her occasional TV appearances still is, "about as close to a Bohemian as it's possible to get in Sheffield") sent him to school wearing lederhosen? But there were several points in the Cocker odyssey at which things could have taken a very different turn. If he had not been caught out at his interview claiming first-hand acquaintance with a book he hadn't actually read, he might have gone to Oxford to read English Literature instead of subsequently securing a starred first from the University of Life via a longterm grant from the DSS.

Had he landed at a different angle when falling 30ft off a window ledge while "trying to impress a girl", he might have ended up in the cemetery rather than a temporary wheelchair. And if the movie bug had bitten a bit more thoroughly during his yearlong film course at St Martin's School of Art in 1988, he might have ended up as a best boy, or even a gaffer. Happily though (to paraphrase the John Miles song with which Jarvis tormented the audience by reading it in its entirety after winning the 1996 Mercury Prize), music was his first love.

By 1992, when Jarvis's gangly charisma was finally beginning to attract the attention it deserved, he had honed to a fine point a unique writing and performing style that combined the minute social observation of Alan Bennett with the sexual bragadoccio of Barry White. Performing as if trying to escape from a bizarre psycho-sexual forcefield, Jarvis would squeeze oranges over his head while mapping out with riveting exactitude a hilarious and sensual landscape of trainer bras and T-reg Vauxhall Chevettes. The band's music was a glittering pick'n'mix of Stylophone and violin. Their songs were episodes of Grange Hill scripted by David Lynch.

It is this just-pre-fame stage of Pulp's development - preserved for posterity on the immortal 1993 compilation Pulp Intro - that time has been kindest to. This is not to deny the power or complexity of later, heroically ambiguous mass anthems like Common People or Sorted For E's & Wizz. But exposure to a wider public gaze posed new and unexpected challenges, and - as what scientists term the Beavis & Butthead paradox teaches us - if stupidity sufficiently magnified can look like intelligence, the reverse may also be the case.

This possibility was seen at its starkest in what Jarvis now refers to warily as "the Michael Jackson business". When Cocker was arrested at the 1996 Brit Awards, having registered his protest at the distasteful spectacle of Jackson posing as the Messiah amid a retinue of subservient children by storming the stage and waggling his stringy bottom, the tabloids - not for the first time or the last - misjudged the public mood. Having initially pilloried Jarvis, they were then obliged to proclaim him a hero. But his new status as a national institution turned out to be something of a double-edged sword. The irony was that a gesture calculated to show that making it big didn't mean you had to lose your sense of proportion, made maintaining that sense infinitely more difficult.

For someone who had always rejoiced in presenting a beautifully realised version of his own life as art, to open a newspaper and see his estranged father in Australia disingenuously begging for forgiveness, or ex-girlfriends bragging about his sexual prowess, must have been a profoundly disturbing experience. "Things did get a bit difficult," Jarvis admits ruefully, "but it was nobody's fault but my own." How does he feel about the Jackson brouhaha now? "It was just a silly thing to do," he smiles. "I don't regret it or anything."

He still speaks with some trepidation, though, of "that feeling of dread when you hear someone shout your name out on the street and you don't know if they're going to say, 'All right?' or smack your face in." Watching Pulp have their photograph taken on a west London street, it's easy to see what he means. The sight of the unmistakably angular Cocker frame elicits a potent frisson of recognition from builders, pensioners and schoolchildren alike, and when someone rushes out of a pub holding a pool cue there is a moment of genuine tension. For all the affection in which Jarvis is generally held, intelligence and idiosyncracy are not qualities his countrymen can always be relied upon to esteem.

There is something very un-English about Pulp's sense of fair play. Jarvis writes the lyrics and gets the attention, but the band write the music together, so the money (not quite a lottery rollover, but certainly a decent pools win) is divided equally. This egalitarian spirit seems to extend to all their business dealings. Pulp's most recent recruit guitarist Mark Webber - was asked to join on an equal footing after years of extra glockenspiel because, explains keyboard player Candida Doyle, "We'd have been bastards not to." And when violinist Russell Senior decided he wanted to move on earlier this year, the band sat around a table and hammered out a mutually agreeable settlement figure without so much as the scent of a lawyer.

Talking to the other members of the band, they seem somewhat apprehensive about dipping their toes back into the choppy waters of public life. "Previously, for a photo session I'd always want false eyelashes." Doyle admits, "but since we've had our break I can't be bothered." Bassist Steve Mackey talks warily of the alcohol-tinged temptations of touring. And drummer Nick Banks must adjust to spending more time away from his wife, child, pub and car collection back home in Sheffield. All are well aware of how lucky they are to live lives relatively free of intrusion, and are supportive rather than jealous of their more celebrated singer.

"People kind of think they've got Jarvis down pat," says Mackey sympathetically. "He's that tall, lanky, stylish, eccentric Englishman from the North who writes touching, endearing and intelligent lyrics, has a feminine side to him and understands women quite well. A lot of those things might be true, but it can't be very nice to feel that everyone's got a handle on you."

The man himself seems to be in agreement. "I have found that aspect of it a bit weird," Jarvis admits drily. "Like when that bloke did me on Stars In Their Eyes, he'd got all the actions and stuff pretty well. And it's strange when you realise that there are certain little physical ticks and movements which sum you up. My immediate reaction was, "I'm never going, to do any of those moves again." I'm sure I probably will in the end, but this sort of thing pushes you across the line from being another human being into being a cartoon character. People see that and they can't see anything else, which kind of castrates you a bit. It makes you self-conscious, and self-consciousness is the death of a lot of things. If you're constantly being reminded of who you are and what you've done, it's hard not disappear up your own arsehole. You have to spend a lot of time indoors because you get hassled so much, and then your brain turns inwards and you start going over things in your mind and wondering about your motivation."

Jarvis doesn't look as miserable as this makes him seem, but it does all sound a bit grim. "It's especially hard if you want to write stuff," he continues stoically. '"I get all my best ideas from just wandering around and seeing little random things, and inevitably in my situation you tend to lead a less random existence. Everything gets mapped out for you, and then if you're not careful you can end up scouring the newspapers for something to write about, which is something I swore I'd never do, because it's taking stuff that's already second-hand and making it third-hand, which is a complete waste of time."

Happily, for those determined not to look at life only through the tinted glass of a limousine, there is always another way. "Bicycles are pretty good," Jarvis notes brightly. "If you're quite famous, people don't really expect you to ride a bike, and you can watch things going on while you're riding. Also, you can always make a quick getaway if you need to. The pollution is a slight problem though." Has he considered wearing a mask? The image of a bandit-like Cocker snatching random insights from the streets of London and then pedalling off at high speed is pretty irresistible. Jarvis shakes his head. "I can't be doing with those. They give you chapped lips," - a wry smile plays at the corners of his mouth as he ponders the damage this might do to his standing in the Lothario community - "and we can't have that."

There's a funny line in Help The Aged where Jarvis seems to be advertising the services of an older lover: 'He'll teach you stuff,' he promises, tongue and who knows what else in cheek, 'although he's looking rough.' Does he feel differently about being single as time goes on? (Jarvis has a longterm girlfriend but seems reluctant to stop being single.) "I think it's more interesting to be single when you're older," he grins, "because there's not as many of you around. Obviously it can lead to a degree of humiliation - trying to cop off with people at a party when you're approaching 40 could look pretty sad. On the other hand the worst thing you can possibly do is waste your life hankering for something you can't have and ignore the things you can possibly do is waste your life hankering for something you have got that are all right." But it's always the things which seem out of reach that you want most, like the romantic ideal of true love, for example. "There isn't really anything romantic about it." Jarvis says soulfully. "It's a very difficult thing to achieve. In fact it's really, really difficult, especially now and especially, especially in the music business."

For all the unresolved contradictions in Jarvis Cocker's heart, his romantic ideal of pop stardom has been triumphantly realised. When his time finally came, after spending more than half his life rehearsing for the role, he found that practice made perfect. "The situation that I've been in," he explains, "is like watching a film, seeing what's on the screen and then suddenly being inside it, being part of the film." And how do the two experiences measure up? Jarvis smiles winningly. "To be honest, I think it's better to be in the audience."