Shane MacGowan's influence on Irish music cannot be overestimated according to a documentary on BBC2 tonight. Not bad for a man once described as `sordid, rowdy and vulgar'

The Pogues partied through the 1980s like the millennium had come early. Their gigs were a riotous assembly of slam-dancing, hard-drinking pub rock, conjuring up all those adjectives beginning with R - rowdy, raucous, rumbustious, rambunctious. Audiences were invariably left with their ears ringing, their clothes drenched in that uniquely sticky mixture of sweat and stout, and an overwhelming sense of fun.

Leading the revels would be the Pogues' charismatic frontman, Shane MacGowan. A rare sight with his jug ears and rotted teeth, he'd more than likely have a Guinness in one hand and a fag in the other. Perhaps using the mike-stand as a support, he'd slur in his inimitable way through "A Pair of Brown Eyes," "Dirty Old Town," or "Fairytale of New York". He was a mess, but a mesmerising one.

A spiky yet undeniably magnetic man, MacGowan reckons that "nothing can beat a good live show, because the audience is more important than the band. I've seen some awful bands play awful gigs, but still had a good time because the audience was great. I got sucked into the thing.

"There's a rawness, an infectious thing about Irish music," he continues. "You can't avoid tapping your feet, shouting, jumping around, getting pissed, or crying in your beer when the band sings a sad one. It's not intellectual, it's very emotional music and people like to let their emotions out. It's cathartic and appeals to people's emotions all over the world."

MacGowan's canny trick with the Pogues was to take traditional Irish music, put it through a blender of punk sensibilities and whip it into something rogueishly irresistible.

His ability to rework conventional forms is just one reason why the singer is the subject of a fascinating profile on BBC2 tonight.

As Billy Bragg puts it in the programme: "The great thing about the Pogues was that, instead of coming at folk music like Steeleye Span or Fairport Convention with respect, they came at it, got hold of it by the lapels, and threw it down the stairs. Nobody had ever gone at it like a bunch of navvies, if I can use that phrase, messed it around, put

the power-drill on it and seen what came out. It was really exciting. It was like going to a punk gig and it was folk music."

It is the sense of excitement generated by MacGowan's music which impresses his peers. Bono, Sinead O'Connor, Christy Moore and Nick Cave pay tribute to the man who was once described as "sordid, rowdy and vulgar". Mark Cooper, executive producer of the programme, believes that "as a balladeer, Shane will endure long past his own lifetime."

The Irish journalist Eamonn McCann, meanwhile, reckons that "in 100 years' time, people will still be singing and still be playing the songs of Shane MacGowan. Who else in Ireland - even Bono - can we say that about? Shane remains perhaps the one authentic genius who came out of the whole celebration of Irishry."

Not everybody in Ireland has spoken in such glowing terms about MacGowan. When The Pogues first started with their unique brand of folk-thrash, they were accused by the establishment of bringing Irish music into disrepute and perpetuating loutish stereotypes. "It was only a tiny minority, a load of old stick-in-the-muds," MacGowan recalls. "There were a bunch of traditionalist folkies who objected to the swearing and the fact that we weren't very good. But that wasn't the point. It's never been the point of Irish music, which is best heard live in a pub with an accordion and people singing and dancing. Irish songs have always been peppered with obscenities - they're raw as well as poetic."

It is, of course, richly ironic that Irish culture has since become the trendiest thing this side of platform shoes. "I think it's really great," enthuses MacGowan, who was born in Tipperary before moving to London as a six-year-old. "That's what the Pogues were formed to do - popularise Irish music. There's an awful lot of Irish pubs around now. There used to be an inferiority thing attached to being Irish, but now it's almost hip."

Now 39, MacGowan is continuing on his crusade to popularise Irish music with his latest album, The Crock of Gold, recorded with the Popes and released later this month. "It's right back to my roots of Irish traditional music," he declares. "It's very head-banging. The rest of the Pogues moved away from this type of music - that was one of the reasons I left the band. It was as much musical differences as the fact that we hated each other. They didn't want to do old Irish songs anymore. We were turning into a rock band and I wasn't interested in that. The whole point was to do Irish music in a contemporary style. I want to do traditional stuff. I'm not interested in progression. There's a danger that people will say I'm stuck in a rut, but I don't give a bollocks."

The other criticism routinely wheeled out about MacGowan is that he is drinking his way down a fast-track to oblivion. He sighs when asked the inevitable question about self-destructive urges. "It's a load of rubbish," he says, wearily. "I don't see what this drink thing is all about. I don't drink any more than anyone else. You don't join a band to drink milk. You join a band to get drunk and have a good time. Drinking is bad for you, but it's fun. Everything that's fun is bad for you. There's only one thing I can think of that isn't - and we all know what that is. But even that's bad for you if you've got a heart condition."

Though he speaks slowly in his Cockney-Irish drawl, MacGowan still makes perfect sense. Anyway, he claims he finds it easier to write when he's out of it. "It gets rid of your inhibitions," he says. "Then you can concentrate on the music. It stimulates the creative forces."

Contrary to popular belief, however, he does not perform drunk. "I don't get completely legless before I go on stage," he maintains. "I just get merry. Still, I'd hate to go on stage completely straight. I did it once and it was murder."

`The Great Hunger: The Life and Songs of Shane MacGowan' is on BBC2 at 10pm tonight `The Crock of Gold' by Shane MacGowan and the Popes, is released on 27 October