CD CHOICE: Viva la Vidaby Coldplay.

On Viva La Vida, Coldplay's fourth album, the band have not just trimmed down the length but also considerably broadened their musical breadth. Gone are the lighter-in-the-air anthems, to be replaced by a more "challenging" sound that finds the quartet flexing new musical muscles and mining a new lyrical seam.

When a band get Brian Eno in to produce their album, it's invariably the case that they're looking for a new sonic upholstering. And to be fair to Coldplay, they really run with all the new ideas swirling around here.

If one song defines an album, then here it's track four, 42, which is clearly the band's boldest work to date. Made up of three distinct sections, it breaks down mid-point into a Radiohead/Kraftwerk-style fusion and is as far away from the likes of Fix Youas is possible to get.

A similar form of daring ambition informs most of the other tracks. Cemetries of Londonis bleakly downbeat and has more in common with Nick Cave than anyone else. The dizzying Lostis propelled along by a soaring church organ and veers off into "tribal beats" territory, while Yesis a sort of neo-shoegazing workout - with lashings of tabla percussion.

Violet Hill, the first single, sounds like something The Beatles recorded in 1967 and lyrically finds Chris Martin in a better place as he speaks of a time "when the future's architectured by a carnival of idiots on show". The title track is perhaps the most traditional Coldplay song here, but fits in well as a lighter counterpoint to some of the more sombre themes.

Not an album, then, for Coldplay's more casual fans, but for anyone who thought the band had unnecessarily drifted into safe, ballad territory over the past few years, Viva La Vidais a reminder that Coldplay still have a credibility point to prove.

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Download tracks: Lost, Yes