Paul Simonon - the only member of The Clash who was in the band from the very beginning until the bitter end - is sitting in a restaurant in Notting Hill answering questions he's never been asked before.

"I've got one thing to say about being the bass player," he says, sticking another roll-up in his mouth. "I didn't want the role of being Entwhistle or Bill Wyman, stuck in the background. That's too depressing and if that was what I'd been offered with The Clash I would've turned it down. Maybe that's the nature of the job, or has been in the past; the bass player as the one that held the fort, so to speak, along with the drummer, letting every body else go lunatic.

"But, y'know-" he blows smoke through that loopy, toothy grin of his "-why can't we all be lunatics?"

Some of you are probably wondering why Paul Simonon - the bass player who couldn't even play when he first joined The Clash - is on the cover of Bassist. Others will be wondering why it took so long. Paul Simonon was one of the first bass players some of us ever remember being aware of. Along with the Stranglers' JJ Burnel and Joy Division's Peter Hook, he revolutionised the way people thought of bassists.

Like JJ and Hooky, Simonon was no back room boy: he looked good, wasn't afraid to take centre stage, and he threw his bass about like he was Pete Townshend. Not only that, but over the years Simonon became a fine bass player, contributing inventive lines to their albums from London Calling onwards, and bringing a vital influence to the band that insured they survived long after punk: his love of reggae.

The Clash, you see, were the only punk band with groove, the first to realise that if you got people to move their ass then their minds would follow, embracing dub, funk, rocksteady and hip-hop long before any other rock band. They worked with Lee Scratch Perry, inspired Bob Marley to write Punky Reggae Party, and became one of the best loved and most influential bands of their era in the process.

Despite all this, Paul Simonon has never been interviewed by a musician's mag - let alone by a magazine for bass players - nor has he ever been an endorsee for a bass manufacturer. Which is hard to believe, considering that - apart from the way he treated it - in the early days he was one of the best adverts Rickenbacker has ever had. It turns out he didn't even like the bloody thing...

"I always wanted to get a set of four legs and make the Ricky into a table, it was so flat," he laughs. "The Precision just had a better sound. Weighed a ton, though. I had permanent burn marks on my shoulders. I always had big welts 'cos I was jumping up and down all the time. There had to be some kind of friction."

The Clash specialised in friction. Recruited because of his attitude and looks, guitarist Mick Jones soon found out the extent of Simonon's abilities. "I had never touched an instrument in my life," says Paul. Jones tried to teach him the guitar, but gave up in a matter of hours. The bass, he decided, would be a bit simpler.

"It was sort of disappointing for me," smiles Paul. "I had these grand dreams of being Pete Townshend. I wanted to do this [pulls windmill shape] and smash guitars and all that stuff. So once I was handed the bass I thought, 'I'll just pretend I'm playing guitar'. Which is pretty much what I did from day one. I swung my arms around just like I was playing guitar. I just took one instrument and treated it like it was another one - not musically, but physically."

Paul also had a nice trick for learning quickly: "To simplify it for myself, I painted the notes on the neck of the guitar. So if Mick said, 'This song starts in D and then it's G and then it's F', I had it all there. I pretty much coloured the whole fretboard in. And after learning parrot fashion, it was only a matter of time before I could take the letters off.

"My attitude was: 'I don't care what other people think 'cos I'm the one who's on stage and they're not'. Staying in tune was a problem: I'd tune up before we went onstage but - with the heat and jumping around and banging it like God knows what - it started going out of tune. We got a review that said, 'I went to see The Clash and I couldn't believe it - the guitarist had to tune the bass player's guitar up'." He laughs: "I felt quite proud about it, actually - it was probably the first bit of press we got."

This display of style, attitude and sheer force was a short sharp shock to both established musicians and to the music press. This was, remember, the hey-day of Prog. "It was a complete contrast. And it showed other people that you could do it." Just six months after frontman Joe Strummer joined, The Clash played their first gig. Paul was just playing root notes and eighths, but he was doing it with style and a force that suited the music. And musicanship wasn't going to hold them back.

"Once at a rehearsal, Joe got a piece of chalk and drew a line on the floor and said, 'On this side is the musicians and on this side are the entertainers'. So me and Joe were on one side, and Mick and Topper [Nicky 'Topper' Headon, drummer] on the other. It was like - who cares about a few wrong notes? We want to see some people jumping around, we wanna see some excitement, we wanna be entertained, not us all standing dead still getting it all right. You may as well listen to the record."

Paul was the image man: the guy that came up with the band's name, who dreamt up their paint-splattered, sloganeering image. He was also notorious for wearing his bass impossibly low - Peter Hook later claimed that he got the idea for his signature strap length from seeing The Clash in Manchester. Paul, like his friend Sid Vicious, got it from another punk legend.

"Me and Sid we used to hang out together," he explains, "and it was Dee Dee Ramone that set the standard for me, and for Sid as well. And we adopted accordingly. It is difficult, but I don't know how people can play it like the guy from Level 42. Maybe there's a half measure where you have it at your waist, but I preferred it like that: you had more room to throw it around, really."

If he wasn't throwing his bass around, he'd be vandalising it, carving his name on it, splattering it with paint and generally treating all hardware "with disdain", as he puts it. "Brand new guitars are just so so dull," he says. "I just wanted to add a bit of character. At least no-one was gonna nick it from you."

Musically, he became a central part of The Clash sound. The Clash were the sum of their influences, and where Mick Jones brought his love of rock'n'roll and glam (the Stones, Mott the Hoople, New York Dolls) and Strummer brought his love for the lyricism of Woody Guthrie and Bob Dylan, Paul added his love of reggae and rock steady to the mix.

"The best place you could hear bass was on the reggae records, and when I got more in control of the instrument, I was able to bring that into the groove as an influence. The good thing about reggae for me, was that they always had something to say. Bernie had essentially said to Joe, 'Don't write about your girlfriend or whatever - write about things that affect you'. And we already had the blueprint - reggae.

"But we didn't want be a reggae group. It was about making our own music, rather than just slavishly copying reggae. But there was a hint of it, a colour."

By London Calling, Paul had learned to play guitar, and started contributing more to the songwriting. ("You don't get paid for designing posters or doing the clothes," he points out. "You get paid for doing the songs.") His first song, The Guns of Brixton, appeared on London Calling and also featured Paul on vocals. Its bass line became famous more than a decade later, when Norman Cook (aka Fatboy Slim) sampled it for Beats International's hit Dub Be Good To Me. Was he surprised? "I was surprised that it became Number 1," he says. "That was quite shocking.

And the fact that it was my performance that they had lifted. The smart thing would've been to copy it and change it slightly, but they just lifted it straight off. So, really, I have done Top of the Pops," he laughs, referring to The Clash's boycott of the show. "But I met up with Norman and we came to an arrangement which was much needed at the time. But I thought it was a really good idea and it was quite reassuring for that to happen to my first song."

The Blockheads' Norman Watt-Roy depped for him on a few songs on Sandanista while he was in Vancouver making a rarely seen film with Steve Jones, Paul Cook and Ray Winstone called Ladies and Gentlemen- the Fabulous Stains. "I remember Joe saying that the difficult thing was saying to Norman, 'Cut all that fancy stuff out'. I had to play them live and by that time I could do it, but it's just not my normal way of playing - I like to simplify it and strip away those fiddly bits."

Sandanista - a triple album on sale for the price of a single album - was a critical and financial disaster, despite being a brave and ambitious collection which - if it was released today - would win Mercury Prizes and have critics rushing to praise it's eclecticism. Combat Rock, the follow-up, was huge, but the band was falling apart. They sacked Topper (because of his drug use), then Mick (because he was "acting like a rock star", apparently), and limped on for one more album and tour before calling it a day.

Afterwards, Paul got together with old friend Nigel Dickson, formed Havana 3AM, moved to El Paso and hung around LA with Sex Pistol Steve Jones. It was there thet both he and Jones were asked to do a bit of session work with Bob Dylan. The sessions were typically weird. "Dylan would show us a song," says Paul, "and we'd run through it quickly, and then he'd go, 'Here's another one...' We couldn't even remember the first one! It went on and on like this - eventually Steve's just going [strums lazy chord] DAAANNNG, and I'm trying to find the root. And that was it. He recorded it live." The album, much to Paul's amusement, eventually came out as Down In The Groove.

Havana AM's Nigel Dickson, meanwhile, had been diagnosed with cancer and given six months to live. He lived for another two, and the pair fulifilled his ambition of touring America.

"I'm pleased that I did that with him," says Paul, "'cos he was an old friend of mine. But then he died and my first son was born. And that was my cue to going back into what I knew most about - painting pictures."

Now a full time artist, Paul still plays the bass at home, messing around with reggae and spaghetti western soundtracks. He helped compile and master the new Clash live album and stays in touch with the others, fielding the inevitable calls for the band to get back together. Paul is pragmatic about it. "If my kids were starving, I'd do it," he says. "But they're not, and I'd like to try and keep my dignity intact, so to speak." He laughs: "We'll probably get together when we're pensioners," he says. "You don't get much for the pension these days, do you?"