Jeff Tweedy has always been a perverse bugger. When Wilco became the toast of the Americana classes, Tweedy did everything in his considerable power to disassociate himself from the scene. He made the two greatest albums of his career, “Yankee Hotel Foxtrot” and “A Ghost Is Born”, and saw his band hailed as so adventurous as to be virtually avant-garde. Clearly, though, being stereotyped as a radical is starting to get on his nerves.

Initially “Sky Blue Sky”, the new Wilco album, sounds like a conscious attempt to get rid of all those Sonic Youth fans who’ve jumped on the bandwagon in the past couple of years. This, you fear, is the record all the Americana diehards have been willing him to make again, as they gritted their teeth through the Krautrock jams and frictional skronk.

Tweedy isn’t one of those artists who lets a desire to confound expectations totally dictate his musical direction. But I can’t help thinking there’s a profound mischief in getting Nels Cline and Glenn Kotche, two of America’s finest leftfield improvisers, into becoming permanent Wilco members, then encouraging them to co-write what is ostensibly mellow country and soul-tinged ’70s rock.

Extremely good mellow country and soul-tinged ’70s rock, of course. For those of us who’ve enjoyed Tweedy’s progress since Uncle Tupelo, “Sky Blue Sky” is another bundle of riches. These are terrific songs, many developing on the Band influence that came to the fore in the more straightforward parts of “A Ghost Is Born”. The cover of Charles Wright‘s “Comment” on the “Kicking Television” live set is a good indicator of what to expect here, too, with Tweedy’s voice having a warm, soulful edge on the likes of “Hate It Here”.

I must admit, I’m one of the people who loved “Less Than You Think”, the epic excursion into rustling noise that gloriously destroyed the flow of “A Ghost Is Born”, so the happy approachability of “Sky Blue Sky” initially seemed a slight letdown. But the more I listen to apparently simple songs like “Please Be Patient With Me”, the more they reveal of themselves. This one feels like the work of a band who are relaxed enough to absorb their experimental impulses rather than flaunt them.

I think I’ve listened to the album eight or nine times now, and at the moment the stand-out is called “Side With The Seeds”. It sways in with a great broken-back piano line, Tweedy singing high and cracked, slowly gathering other instruments as it goes. Then after a minute and a half, the band shift a gear and start climbing towards the peaks, with Tweedy and Cline indulging in the kind of Television-ish guitar interplay that made live versions of “Handshake Drugs” so striking on recent tours. By the end, Cline (or at least I reckon it’s Cline) has slipped the leash and is playing one of those needling, high-end solos at which he excels.

Again, though, it’s striking in its economy. “Side With The Seeds” only lasts for four minutes and 15 seconds, but it could go on for another five. By the time Wilco reach the UK in May – by the time “Sky Blue Sky” is released, in fact – perhaps it will.