More proof of Blur's infinite horizons is provided by Think Tank, their seventh album and their first recorded as a three-piece. While defying the rumors that it would be either 1) their "dance" album or 2) their "world music" album, it is their grooviest so far, with an eclectic variety of rhythms and textures underpinning melodies to melt the heart and wobble the lower lip. The spirits of Can, Joe Strummer, Eno and Orchestra Baobab hover, but the result - though unexpectedly languid and sunny - is pure Blur. It is their first - hopefully not their last - cabriolet record.

Blur Its story begins in November 2001 when, with Damon Albarn's Gorillaz commitments on hold, the band convened at 13, their West London studio. Founding guitarist Graham Coxon was briefly in attendance, and plays on closing Think Tank track "Battery In Your Leg." With Ben Hillier (Elbow, Tom McRae) performing the lion's share of production tasks, the band, minus Coxon, resumed work in earnest. In short bursts of intense toil over a period of 12 months, with William Orbit and Norman Cook lending occasional assistance, a host of sonic experiments were eagerly applied to what Albarn now describes as "our most direct set of songs since Parklife".

What emerged was nothing if not cosmopolitan. Think Tank contains Brothers And Sisters, a funk noir about global drug addiction ("Cocaine is for murderers / Codeine, for the jurors") alongside a paranoid hardcore Dr Who song called We've Got A File On You. Elsewhere, there are love songs, reflections on our stewardship of the planet, and, everywhere, all sorts of curious noises where electric guitars used to be. With 20-odd tracks already nearing completion, Hillier and Blur decamped to Marrakesh, Morocco for September and October 2002.

Clash-loving Norman Cook dropped by again, while an Andalucian string group added arabesques to stirring, compassionate "Out Of Time." Three new songs emerged, including the jump-up, punk rockin' "Crazy Beat" the first US single - and Strummeresque "Gene By Gene." The year ended with Blur's peripatetic studio being transferred to a Devon retreat and Think Tank was finished. "It's by far the best record we've ever made," says Dave Rowntree, not the member of Blur most prone to hyperbole (that's Alex). "I'd compare it with Parklife. In both instances we threw away the rule book. But with Parklife, that was just to piss off our record label. This time we had to."

Blur as we know them were born in 1989 when the band signed to Food/EMI. Showing immense resilience for ones so punchable, they survived early controversy (a scantily-clad woman on a publicity poster for debut single "She's So High"), a hit single ("There's No Other Way," UK #8) with at least two world-class riffs in it and a drummer hell-bent on spending as many nights in police cells as hotel beds. Debut album Leisure announced the arrival of a spunky, inventive new band with pop suss warped by art-punk eccentricity. Yet Blur had more in them: namely, a revolution in the sound of English popular music.

Like most revolutions, it was hard won. 1992 should have seen Blur ascend to the next level but mismanagement had left them close to bankruptcy and an infernal American tour, arranged to plug the financial hole, saw an unhappy, drunken band at each other's throats. It is no coincidence that the most desolate song on Blur's heartbreaking 1999 album, 13, is called 1992. Their salvation, as is always the case with Blur, came through music. Second album Modern Life Is Rubbish reintroduced the idea that specifically English rock music could be cool, and by the time their third album, the legendary Parklife, emerged on April 25, 1994, the rest of the UK had caught up. Defined not only by album sales but culturally too, they were the biggest band in Britain.

The Great Escape (1995) refined the sound palette and conceptual framework of what the press dubbed Britpop, but Blur - unsettled by the experience of pop fame and driven on by naturally subversive instincts - were already moving on. 1997's Blur album even had a track called "Movin' On", and was an about-face - scuffed and noisy and un-English. In Israel, reports Dave Rowntree, journalists excoriated them for killing Britpop but America - hitherto resistant to their charms - took the explosive "Song 2" so much to heart that they asked for it to soundtrack the unveiling of a new Stealth bomber. Blur declined.

Not about to repeat themselves, Blur followed up with 13, a more radical adventure in sound influenced by the cold vistas of Albarn's then semi-home, Iceland, and the disintegration of his relationship with Elastica vocalist Justine Frischmann. Blur parted company with Stephen Street, their co-producer since "There's No Other Way," and welcomed aboard William Orbit, who refereed a truce between organic punk-pop and new-fangled technology that holds firm today.

In 2003, Blur are two-thirds teetotal, one-third a father, three-thirds gagging to test their brand new configuration - saxophonist, percussionist, vocal harmony, a surprise around every corner - on live audiences. But first there's Think Tank, a groundbreaking record from a groundbreaking band. Play it loud. It sounds better that way.