The double life of New Yorker Laura Cantrell might be straight out of Gotham City in Tim Burton's movie Batman. By day she works for the Bank of America's equities research department. By night she rides into the lonesome skyscraper canyons and hits the saloons of New York to sing bittersweet country music. In between, she broadcasts her own show on the influential Radio WFMU station.

If this is Cantrell's secret triple identity, then it won't stay secret for long, judging by the sell-out at the Ramshorn, as the most successful yet Big Big Country Festival swung towards its finale. And if Shania Twain is the Bardot of post-new country then Cantrell is its saloon-savvy Lauren Bacall - whom she resembles, with a smoky look, and with stinging lyrics that tell you not to get too close.

For instance, the title track of her debut album, Not the Tremblin' Kind, is all about female strength, employing S&M imagery to describe power and submission. Equally perversely, she has released her album on the embryonic Glaswegian label Spit and Polish, run by the country fanatic and Radio Sweethearts drummer Francis MacDonald. The connection was established when Cantrell played the band's music on her radio show, and they backed her with their distinctive shuffling swing, her brittle voice sometimes clattering up the high registers as if surprised by her Glaswegian cohorts.

The music is about familiar busted hearts and road stops in Reno, but is sung with direct honesty and the tiniest twinkle in Cantrell's eyes. She was born in Nashville and was weaned on the bluegrass of Earl Scruggs and Lester Flatt, and she doesn't attempt to hide it.

Cantrell delivered a captivating show, with a hint of the nervy edge of the great Mary Margaret O'Hara. Hell, she proves that even Wall Street analysts can get the honky tonk blues.

Big Big Country Festival ends tomorrow.