KT Tunstall, Regent's Park Theatre, London

Something every man learns, from experience, is to beware of any woman over the voting/drinking age who calls herself KT instead of Katy.

It's analogous to dotting the letter "i" with a smiley face on postcards, or using a Hello Kitty emoticon on the Internet, or having more than three stuffed toys lined up on her bed. At best, they're harmlessly (if irritatingly) wacky. At worst, they're mentally ill. It doesn't matter how attractive they are: avoid.

I'll give KT Tunstall ("It's got a bit more attitude than Kate," she has feebly explained) the benefit of the doubt, and place her in the wacky camp. "Hi, I'm KT, the ents officer from Strathclyde Uni! Only meeee!"

There is something to be said for tonight's gig, but most of it is earned by the venue. The Regents Park Open Air Theatre could, if its trustees so desired, become a leafy rival to Somerset House for civilised open-air London gigging, with hedgerows and fairy lights instead of cobblestones and doric columns.

It's a pity then that such an enchanting amphitheatre has to echo to the sound of Tunstall, a multi-instrumentalist in her twenties from St Andrews, who makes earthy, earthenware, basketweave, raffia, oatmeal, pot-pourri music reminiscent of Rickie Lee Jones, Annie sodding Lennox and, when she sits down for the encore alone with an acoustic guitar, the full-fat Joplin.

Essentially she's adopting what used to be called "negro spirituals" in more innocent, more racist times, and imbuing them with Celtic folk overtones. The sound of the man working on the chain gang, mixed with the rattling of bourgeois jewellery.