Alt.country traditionalists dismayed by the avant-garde inclinations Jeff Tweedy showed on Wilco’s Yankee Hotel Foxtrot will be demoralised further by the appearance of Loose Fur. A third collaboration between Tweedy, Jim O’Rourke and drummer Glenn Kotche, it takes the fluid, impressionistic style of Yankee Hotel Foxtrot and O’Rourke’s Insignificance to a brittle new level.

Actually, Loose Fur was their first work together, recorded some three years ago, long referred to as the “Nuts” project and delayed until the protracted YHF campaign was over. The three songs sung by Tweedy and two by O’Rourke, plus one deft instrumental, have a surprising unity: a rolling, hazy style which circumnavigates usual verse/chorus/verse dynamics. Instead, typical Loose Fur pieces begin as sketchy songs before undergoing a kind of gracious metamorphosis into long, semi-improvised passages.

Only “You Were Wrong” is spared an elaborate coda, a perfectly-realised fragment of Tweedy melancholia that, distant dysfunctional clang notwithstanding, should sit easily with Wilco’s more conservative heartland?though the superb opener, “Laminated Cat”, found its way into a few Wilco sets last year. But to imagine Tweedy as some sort of humble, straightforward balladeer being led astray by the arthouse trickery of O’Rourke is to miss the point of Loose Fur. The group allows O’Rourke to indulge his songwriter instincts and Tweedy to exert an often-suppressed experimental imperative.

So when O’Rourke essays the frail “So Long”, his acoustic reverie is interrupted by an electric guitar line from Tweedy, whose pointillist soloing recalls no one so much as improv hero Derek Bailey. Kotche, too, is complicit in the plot, sounding as if he’s more interested in throwing his drums down a staircase than playing them. It takes some six minutes before the trio glide into unison behind O’Rourke’s breathy harmonising.

The effect is brilliant. You can look at it two ways: as a document of shifting tensions between songform and skronk, a big virtuoso tease that may well aggravate as much as illuminate Tweedy and O’Rourke’s contrasting fans. Or as the discovery of the common ground between songwriters and experimentalists.