He hates slack service in restaurants, nostalgia for the past and the other Sex Pistols. As John Lydon prepares to reveal the truth about punk in a television documentary, Lisa Verrico discovers where things went Rotten.

Simple truth: Lydon disagrees with theories behind the rise of punk. "If we had an aim, it was to force our own, working-class opinions into the mainstream, which was unheard of in pop music at the time."

John Lydon has never been easy to ignore. Today, with his hair bleached bright blond and startlingly spiked, he should be impossible to miss. Nevertheless, for a full 15 minutes, the staff of an all but empty Japanese restaurant in London's Holland Park have failed to notice his attempts to attract their attention. Finally, tired of waiting for his first drink of the day, Lydon stands up and takes action. "Why won't anyone serve me?" he wails at a waitress rearranging cutlery on a nearby table. "I know I've been away for 20 years, but I'm not that easy to forget, am I?"

"It's not nostalgia," he snaps, draining his glass. "It's history. There's nothing wrong with looking back if you do it with an honest eye," he continues. "What I want to rid the world of is sentimentality. I hate it. It misses the point. The only reason I agreed to the documentary was because Channel 4 gave us the freedom to tell the Sex Pistols' story as it really was. It's the band's chance to set the record straight. We don't praise ourselves or wax lyrical about our influence. We just tell the truth. So much rubbish has been written about punk in the past 20 years, mostly by people who weren't even there. The Pistols had nothing to do with the Situationist movement on the Left Bank of Paris in the Twenties. Honest, guv."

Lydon may be able to give a good reason for reviewing the Sex Pistols' explosive career, but he can't easily explain why he briefly reformed the band without losing face.

"Okay, I contradicted myself fabulously with that," he admits, gulping down a second glass of saki. "I vowed I would never try to turn back the clock. But we weren't really reforming. It wasn't a comeback tour, it was a 'f*** off for ever' tour. Until then, the Sex Pistols had never ended properly. It simply fizzled out into a load of nonsense. We now feel that it's over for good."

Lydon wasn't in it for the money then? "I said at the time that it was for money, but that was complete rubbish, whether you believe me or not," he insists. "I knew that was what everyone would assume, so I got my foot in first. I pre-empted the dissing b*****ds. Besides, it wasn't the money you'd imagine. Kiss were doing a reunion tour then and we made nothing like they did.

"To be honest, I thought we'd be playing to empty halls. I didn't care if no one even came. The aim was to resolve certain issues within the band, which we did. All the old animosities came out. By the end of a nine-month world tour, we knew we really did despise each other."

However, the fate of PiL is not as clear cut. Formed by Lydon after the Sex Pistols' sudden demise in 1978, the band featured permanent members such as the former Clash guitarist Keith Levene and a then unknown bassist Jah Wobble. Long before it petered out 14 years later, PiL had effectively become just a vehicle for Lydon's collaborations with other artists. He now claims that if Plastic Box sells well, the project could make a comeback. "At the moment, I have a deal to release records under my name," he says. "But working with other people appeals to me more. I'd never make another Sex Pistols album, but I'd like to see PiL back in action."

From the outset, PiL was a surprise success, scoring a top ten UK hit with their debut single Public Image, an angry rock song notable for Lydon's distinctive vocals and its newspaper sleeve. In 1979, the album Metal Box - sold as a set of three 12in discs packaged in tin film canisters - saw the group hit on its trademark antagonistic mix of heavy bass, noisy guitars and experi-mental techno. For the next decade, a constantly evolving line-up had big hits with This Is Not a Love Song and Rise, a track which boasted Ginger Baker (once of Cream) on drums. Later, a collaboration with hip-hop icon Afrika Bambaataa resulted in the Time Zone single World Destruction, while a stream of guest musicians on PiL projects went on to include Steve Vai and Ryuichi Sakamoto.

After PiL's last studio album, That What Is Not, came out in 1992, Lydon continued to record, releasing an underwhelming solo album, Psycho's Path, two years ago. Currently, music is little more than a hobby to him. "I occasionally put out techno singles under different names," he says. "I have always been into disco - PiL was basically a dance band - but people don't want to hear me make that type of music. If I put my own name to a track, it guarantees disapproval."

The eldest of three brothers, John Joseph Lydon was born in London in 1956 and brought up in a Victorian tenement in working-class Finsbury Park. His father, John, was a labourer who had moved to England from Galway with his wife, Eileen. For the first 11 years of Lydon's life, the family shared a tiny, two-room flat with an outside toilet. Lydon attributes his outsider status to contracting meningitis as a child, which held him back a year at school and gave him his trademark hunch and poor eyesight.

By the age of 16 he had dyed his hair green, moved into a squat in King's Cross with Sid Vicious and was making money busking with a violin. On a day that he was wearing a T-shirt emblazoned with the words "I hate Pink Floyd" while busking on the King's Road, he was spotted and taken to see Malcolm McLaren. The Svengali manager persuaded him to join a nascent Sex Pistols as singer and change his name to Johnny Rotten. The Sex Pistols' controversial career was to last less than two years, but produced one of the most influential albums of all time in Never Mind the Bollocks.

Since PiL's last album, Lydon has preoccupied himself with other interests. "I'm not exactly lazy," he insists. "At home, I ran a syndicated radio show called A Rotten Day. It was a minute every morning of me telling the truth about independent rock. It was networked in the States, but blacklisted in L.A. because they thought it was too irreverent."

His latest venture is a television series on VH1 which is due to be aired later this year. "It's a chat show," he says, "but with just me doing the talking. It's based on the new millennium - I get rid of all the objects I think we won't need in the future." For Sex Pistols' fans the result may be painful to watch. "One of the first things we filmed was a bonfire I built on the beach by my house," recalls Lydon with glee. "I got my brother's kids to toast marshmallows while I toasted the Pistols. I can't tell you the pleasure I got from tossing A&M copies of God Save the Queen on to the fire (Beano's, the UK's leading secondhand record shop reportedly recently sold a copy of this disc for £2,500). I'd like to destroy rare items of Sex Pistols memorabilia every week. Yes, I could sell them and give all the money to charity, but it's more fun to burn them."

Predictably, Lydon is just as dismissive of modern rock music, in particular Oasis. "I like them as chaps, but I loathe their music," he says. "My mum and dad used to play that Sixties s**t and it drove me mad then. The Sex Pistols opened a lot of doors 20 years ago, now I have to sit back and watch the likes of Oasis close them. They're so naff."

The Spice Girls, on the other hand, get a Lydon seal of approval. "I like the Spice Girls because they don't pretend to be anything they're not," he explains. "They're just good fun and they make kids' lives a bit less miserable. The Spice Girls are music hall in the same way that the Pistols were," Lydon grins. "They are so English, they could not come from anywhere but this country." He cackles. "In fact, I like them so much I bought the dolls."

Oddly, for a musician who thrives on attention, Lydon himself appears to have no interest in pop-star status. "I'm not into flash cars or big houses. Even with the Pistols, I didn't think of myself as a pop star. How could I?" he asks. "At the start, I never imagined we would amount to much. By the time we were famous, I was smart enough to know that being admired wasn't what it was about. The rest of the band knew that too. Well, everyone but Sid." Lydon's grin fades. "The whole pop-star thing caused him a lot of problems, probably because he hadn't been with us from the start. He missed the training. Looking back, I could have educated him on that, but what can you do? Ultimately, everyone makes their own choices in life."

With PiL, Lydon saw the opportunity to put into practice what he had learned with the Sex Pistols. "The Pistols was a crash course in what can go brilliantly right and horribly wrong with a band," he says. "It was an incredibly volatile two years. You can come out of that a shattered human being or damn wise to the ways of the world.

"The idea behind PiL was exactly the same as it was with the Sex Pistols - only much more focused," he continues. "I was determined to limit our public persona and concentrate on not just the music, but the attitude and the drama within the group. I wanted less pop. That's what destroys you in the end. With the Pistols, the pop part came accidentally. It was fun for a while, but we naively let it get out of control. We were continually accused of nonsense. I remember reading in the Mirror that I was a heroin addict," he says with a shake of his head. "Of course, they meant Sid, but they had no qualms about getting it wrong. We were unprotected because we were supposedly the bad boys of the day. In fact, we were just four confused young lads."

Lydon's recollections of punk suggests that the Sex Pistols documentary, as yet unscheduled by Channel 4, should make great viewing. "The truth about punk will get out," insists Lydon. "It was not an intellectual movement orchestrated by Malcolm McLaren. We didn't set out to be seen as some great, culturally significant force. If we had an aim, it was to force our own, working-class opinions into the mainstream, which was unheard of in pop music at the time."

He shakes his head again. "I don't recognise half of what punk apparently became. You need a dictionary to understand most of England's Dreaming [Jon Savage's acclaimed account of the history of punk]. "I mean, what does that have to do with growing up in a grotty council flat? Not a lot, missus."

When Lydon left the Sex Pistols in 1978, midway through an American tour, he had made next to no money. Later, he would sue McLaren for what he refers to as "all the criminal activities that took place". "Winning the court case against Malcolm gave me the rights to loads of old, unseen film footage of the Pistols," explains Lydon. "It was all just stored away. It took me years to sort through it. Some of it is stunning. Most of our gigs were recorded live, just on a cheap camera and one microphone. Watching it made me realise how good we were. I thought I'd feel embarrassed about myself," he grins, "but I didn't. Ten years ago, I wouldn't have wanted to look, but I guess it's like your parents showing you old family photos. You get less insecure about yourself as you get older."

Lydon, insecure? Surely not. "Absolutely," he shrieks. "I've always been incredibly shy. I was the quietest kid in school. The arrogance is just a front. In the Pistols, I used it as a wall to hide behind. Some people use drugs and drink, but I find them too time consuming."

It is hard to know whether or not Lydon is telling the truth. If he is shy by nature, he hides it well. By the time the interview is over, several bottles of saki lie empty on the table. He has taken to hurling abuse at the restaurant staff and has to be lured to the photo-shoot with the promise of more alcohol. En route, he drops his trousers at passers-by. Two decades after the Sex Pistols, Johnny Rotten is alive and well.

Plastic Box is out now on Virgin.