Nigel Williamson -Scotland on Sunday

HOW splendid to find Bob Geldof back to his old self when we meet at his favourite members-only club in London's Soho. Loud, opinionated, irreverent and liberally tossing out more expletives than a fired-up Liam Gallagher, he's holding forth on the subject of his old group, the Boomtown Rats. The greatest band the world has ever seen, the way Sir Bob tells it. "Bono called us the first of the moderns," he boasts. "We sold more records than The Clash and we were the first new wave band on Top Of The Pops. The thing was, we could play when all of those other punk groups couldn't."

The last time we met two years ago he was in a very different frame of mind. Then he was promoting Sex, Age and Death, an intensely personal collection of songs which recorded his anger, hurt and bewilderment at the tragic events set in motion when his wife Paula Yates left him for Australian rock star Michael Hutchence. What happened next was the rock'n'roll equivalent of a Greek tragedy. There was a bitter battle over the custody of the couples three children. Then Hutchence hanged himself. Three years later Yates was also dead, after a heroin overdose.

Chronicling these events in song was clearly both therapy and a cathartic reliving of the agony. A subdued and introspective Geldof described "chasms of grief, universes of pain, oceans of emptiness". He had only kept functioning, he claimed, for the sake of his children, when all he really wanted was "to disappear to the furthest corner of the planet and howl into the grey void". The album itself, his first in eight years, made for harrowing listening.

Today, at 52, Geldof has finally been able to move on. "That it happened was tragic and cruel to everyone," he says. "But there's no anger towards individuals. Anger is a useless emotion."

He's got both his confidence and his mouth back and he's in a mood to take stock of the past and re-evaluate his life and career. "Its only recently that I've started listening again to those old Boomtown Rats records and the other music from the punk era," he says, "and it sounds surprisingly good - much better than I remember it. It still sounds exciting. It was new and radical and dynamic, and the Rats were part of it. I'm proud of that."

At the end of last year Geldof supervised the release of a new, 19-track Best of the Boomtown Rats compilation. Soon the bands entire back catalogue will be reissued in new, digitally remastered editions. Geldof's even back on the road playing the old songs again, including an appearance this week at Glasgow's Celtic Connections festival. These days, of course, he's more famous for being famous than for being a musician. It's something he readily accepts. "Once I entered the social arena it became inevitable that would overshadow the music. You become a phenomenon and I will always be the Live Aid guy."

Geldof insists he's not at all frustrated by the publics perception of him. "The reality is that more people go fishing than buy records," he says dismissively. "We think everyone is into this pop star thing. But it's very narrow really. So to be honest, I couldn't care less about being remembered." When I fail to conceal my disbelief at this statement, he laughs loudly. "All right, I give in. I do feel I've contributed to the gaiety of nations and I cant deny I get a vibe out of all the acclaim."

But what of Live Aid? This year marks the 20th anniversary of Geldof setting his career with the Boomtown Rats to one side to bring us those harrowing pictures of starving children in Ethiopia. Does he feel he achieved anything? "Listen," he says forcefully. "The world is never going to be a better place - and it's not the job of musicians to do that. It's not our place to talk about those things. If you create great art out of political or social events, then good luck. Art can articulate the kind of society we've created, but changing it is a different thing."

A lot of musicians, such as Blur's Damon Albarn and Chris Martin of Coldplay, were outspoken in their opposition to the war in Iraq. One might have expected Geldof to have been prominent among them. "Well we now live in a world of managerial politics," he says, "and that has produced a breakdown of trust. It's very hard to see how you deal with that."

Those words were uttered in late October. So it is with some surprise that I next encounter Geldof only four or five weeks later at a benefit concert in Cape Town organised by Nelson Mandela and his anti-Aids foundation. And wouldn't you know it, there's Bob on stage in a crumpled white suit, making a speech twice as long as Mandela's and ranting and raving against the iniquity of Western capitalisms refusal to supply anti-retroviral drugs free of charge to Aids sufferers in the Third World. "What could be more political than that?" he demands. Back stage I remind him of his comments only a month earlier and ask what has made him take it upon himself to try to change the world again. "Because Nelson Mandela asked us. He is one of the few giants on the planet today and you can't deny him anything," he snaps back.

Yet Geldof insists that, in his own mind at least, he remains first and foremost a musician. "That's who I am and its what I do. I write songs - and a few of them have entered the culture." Listening to the reissued Boomtown Rats records once again, its surprising how well many of them have stood the test of time. In contrast to much from the punk era which may have seemed energetic and rebellious at the time but today sounds merely crude and badly played, Geldof always wrote proper songs that would surely have made their impact in any era - Mary of the Fourth Form, Rat Trap, Looking After Number One and I Don't Like Mondays.

With the benefit of hindsight, such records don't sound very punk at all. "That's because we weren't punks. We had saxophones and ballads and harmonies," says Geldof. "Punk was a cool metropolitan thing in London. We came straight off the boat from Ireland and were excluded from the metropolitan cabal, so we played in Derby and all those other places."

The Rats Irish origins were crucial to their success, he believes. "Punk happened in England because rock was overblown. But it was a response to something quite different in Ireland. Even in Dublin there was no rock culture as such. It was like Britain in the 1950s. As there were no jobs, everybody with any talent emigrated." Geldof's escape route was music. At the Boomtown Rats first gig, a girl approached him after their set and said, "You're beautiful, I want to f*** you." "I took her home and I knew I'd found the job for me. It was as advertised," he recalls fondly.

These days he has a 14-year-old daughter who's almost as old as the Mary of the Fourth Form he once sang about. I wonder what his children make of his old records. "They take the piss out of me," he admits. "They're more into the White Stripes and the Hives."

Nevertheless, he's justifiably proud of the Rats legacy. "Bishops wrote letters. The Irish Times wrote an editorial. We were banned," he says with pride.

"People think I was arrogant, but that wasn't it at all. I was just enjoying winding everybody up.'