Damon Albarn has been through it, all right. The innocent indie days when Blur strutted cock-a-hoop through Camden, all desert boots and snotty middle-class attitude, are long gone. The Britpop hype soon backfired, while the Blur vs Oasis debacle left Albarn with jellied eels on his face. Most recently, there was the painful break-up with his long-time girlfriend, Justine Frischmann from Elastica. At the tender age of 31, Britpop's Jack the Lad has been through enough pain and pressure for 10 Kurt Cobains: so why shouldn't he sing about it? For their sixth album, fate-temptingly entitled 13, Blur have dropped the jolly hockey sticks and headed off towards the darker regions beyond the bike shed. 13 deals in stark, avant-garde images of loss, loneliness and regret, boasting an honesty and passion which would make Del Boy blush with embarrassment.

The signs of a sea-change were there on their eponymously-titled 1997 album: songs such as Death Of A Party and Essex Dogs sounded the funeral bells for Britpop, while Song 2 signalled a sharper, angrier and ultimately more accurate stab at sheer punk energy. Blur were growing up, getting deadly serious, and they were rewarded for their effort with their best-selling album to date.

As an added bonus, Song 2 was picked up by the American National Hockey League as their theme tune, and also used in the trailer for the blockbuster movie, Starship Troopers. The smart move would have been to tailor-make the next album to suit the American market, a radio-friendly mix of Camden swagger and grunge influences, perhaps. Instead, Blur made 13, their most daring, difficult and downright awkward album to date. The popular perception is that this is Albarn's "break-up" album, the product of his painful split with Justine. The reality is that 13 represents a real shift in Blur's centre of gravity, a re-alignment which brings them smack dab into the sound which suits them best. The first single, Tender, an eight-minute bluesy gospel dirge, shocked fans with its sheer passion, something no one would ever have expected from Blur. As we speak, critics and fans are still trying to get their heads around the quirkiness of Battle, the Beef-heart bravado of Swamp Song, and the folksy frailty of No Distance Left To Run.

Last week, Blur performed the new album almost in its entirety at the BBC's Hippodrome Theatre in London's Golders Green, before a select audience which included Keith Flint from The Prodigy, Neil Hannon from The Divine Comedy and ex-Specials singer Terry Hall. The concert went out live on Steve Lamacq's show on Radio 1, and the audience greeted the new material with polite adulation. Speaking to Albarn a few days after the show, I asked him if he was happy with the crowd's response to Blur's new adventure in hi-fi. "Yeah, it was OK," he conceded. "I mean, we weren't playing it for hands-in-the-air reactions. I think we're trying to prove that you can play a whole body of work from beginning to end and be deadly serious about it, yet still enjoy it. I think it's the most pleasurable body of work that we've done."

While acknowledging that 13 is probably the most out-there album Blur has yet done, Albarn shakes off doubts about whether the band's fan base will follow it to the brink. "I'm getting some reports back about chart positions and it's number one in a lot of countries this week. Initially some people will be a bit freaked out by it, but as long as they give it a chance, I think it'll be quite rewarding."

Albarn seems to be similarly philosophical about the idea of making it to the top of the American market with a tailor-made album. "I don't know about getting on top - this is our idea of being on top. I don't know if it's someone else's, but that's their problem really."

To most people, Blur were top dog just around the time of Parklife. With lager lout anthems like Boys & Girls, and a readymade theme tune in the title track, Blur were Britpop's winning team - until Oasis strutted in from ?????oop north and upset their apple-cart. Blur tried to rally the forces, winning the battle of Britpop with their number one single, Country House, then losing the war with The Great Escape, an ambitious but ultimately shallow effort.

"There were things wrong with it," admits Albarn. "It's very frustrating that we made those mistakes at the time, but we learned very quickly from it. There's no such thing as a world-dominating record; people think there is, but really there isn't.

"There was a mythology about The Great Escape which we didn't mean to create - it was sort of built around the success of Parklife and what followed with Oasis; a whole movement. So whatever we did we'd have still been in the epicentre of it. It was something that brushed on everyone from Tony Blair to films like Trainspotting. I think for us it was never a complete statement - we just moved on as soon as we felt we'd done enough with it.

"Those albums (Parklife and The Great Escape) were quite angry in their own way. They used fairly cheerful idioms to express that sort of frustration, but the characters are not positively portrayed in those songs. They're all messed-up people." In contrast, both Blur and 13 are sparsely populated with characters and caricatures. It seems that Albarn's lyrical mirror is being turned back on itself while the style also seems less calculating and less contrived than before. Blur seem to be working more by instinct than by expectation.

"I think it's just that I've realised that you can't be calculating about life. It's a youthful thing - you think that you've got it all sorted out and you can control your life, when really you can't. So I think at the time it was a very natural thing to behave like that. I put it down to being a bit naive really."

There's an indecent amount of soul-baring on the new album, but Albarn delivers songs like Tender and No Distance Left To Run with real feeling, in a voice a million miles removed from the Essex twang of old. So is the album really about Justine, as the rock press insists? "No, no, no," insists Albarn. "There's a few songs about it, but the rest is about my life. (The break-up) was obviously a part of it, but it hasn't been for quite a while. But they just want that, they love it, and I'm sure with Suede's record coming out it'll be mentioned again." (Justine also dated Suede's singer Brett Anderson).

"It has never worried me what people think, otherwise I'd be so restrained and it would be no fun, but I think this is the first time that I've been slightly wound up by the fact that people have said `it can't possibly be him', just because they're very personal songs."

While 13 has been a catharsis of sorts, Damon Albarn is still scarred by both his break-up with Justine and the demands of fronting the quintessential British band of the decade. As part of the recovery process, he has made the tough decision to quit touring. "I'm never doing that again," he states, adamantly. "I mean, I'll play gigs, but touring, never, never again. I just want to get on with living and spending more time in the studio - when you go on tour it excludes you from playing in the studio for about eight months, and you can miss out on quite a lot of ideas."

It is obviously an important album for Albarn personally and one in which there is a sense of closure. Typically, he broaches the idea in up-beat fashion: "I don't think you ever get complete closure on anything until you die. My way of dealing with any kind of history is to concentrate on the future and accept that I'm learning all the time." So: time to move on, then? "Oh yes, absolutely, and not f**k it up this time."

Blur play the Point Theatre in Dublin on Thursday July 22nd, and tickets go on sale tomorrow 13 is out now on Food Records.