Katie Melua, Hammersmith Apollo, London <!-- none onestar twostar fourstar fivestar -->

At one of west London's largest venues, you would not normally bat an eyelid at material that took in child prostitution and mental disorder. Except when delivered by a music-school graduate mentored by the former Womble Mike Batt.

This was the scenario enjoyed by the stunned crowd. For instead of the sickly jazz-lite of Katie Melua's blockbuster debut, Call off the Search, here was seedy country and even some Rolling Stones. In no way could her follow-up album, Piece by Piece, prepare us, even though Melua had opted for a more bluesy sound and feel. The artist, moreover, had grown into a seasoned performer. Her laser-guided vocals carried extra emotional weight - proof she may have legs as an artist.

If a pin had dropped, it would have been loudly shushed, an atmosphere broken only between songs when Melua betrayed her bland character. The singer-songwriter spoke in such a dry manner, she could have been chairing a Neighbourhood Watch meeting. But it put her fans at ease, at least until she tackled racism on "Spider's Web". It came with clichéd ebony-and-ivory metaphor, but nonetheless suggested a thoughtful stance.

Melua's writing certainly showed up Batt's trite contributions, notably on "Halfway up the Hindu Kush", a throwback to stilted pre-Noël Coward comedy, and the irrelevant stats of "Nine Million Bicycles". She and her band, meanwhile, had fun chopping and changing between different styles on a compellingly odd set of covers.

Her take on "Fancy", Bobby Gentry's tale of a daughter groomed for hire, eased us in. Then came the bombshell of "Lucy in the Sky with Diamonds", a mandolin reducing the song to "Puff the Magic Dragon" status. Another mistake was "19th Nervous Breakdown". The Stones' throwaway lines were done no favours with an odd boogie-meets-hillbilly arrangement.

Perhaps she should have played "The Closest Thing to Crazy" earlier rather than at the end of her set, as it was the only song her audience responded to with anything like rapture. Even as they left, they seemed befuddled by Melua's break from her safe, cuddly image. An attempt so clumsy, it became perversely enjoyable.