Clare Maguire, Bush Hall, London

Half-a-million MySpace hits is one modern route to the Cinderella story. It let Birmingham's Clare Maguire sign to a major label at the once unremarkable age of 20. Then she was led through music's corridors of power, drinking with Jay-Z, squired by Rick Rubin to Leonard Cohen's rehearsals, offered a song by an enchanted Jarvis Cocker. Tentatively pushed in 2010, her album (with Ellie Goulding's producer) is finally due next month.

The advance publicity protests too much in emphasising Maguire's "realness" and "authenticity", as if she's a reincarnation of her heroine, gospel great Sister Rosetta Tharpe. She inhabits a different but parallel fairy tale to The X Factor, enjoying her huge voice as much as any of her generation on that show.

For tonight's first headlining gig, Maguire slips on stage in crucifixion pose, burlesqued by a twitch of her glitter-skirted hips. A reel-to-reel tape is as ornamental as her guitarists in a sound based in the huge thwack of 1980s pop production, which her voice is even bigger than. Though she hugs herself as if frozen by the emotional terrain of "Ain't Nobody", she doesn't have the chill of synth-pop siren Annie Lennox, to whom she's been compared. Statuesque poses in the black basque worn in tribute to a somewhat different heroine to Sister Rosetta, stripper Dita Von Teese, soon give way to matey banter with a cheeky drunk about his Twitter account.

The template behind the music, meanwhile, seems to be Florence + the Machine's cover of "You've Got the Love". Her own version of Fleetwood Mac's "Big Love" is greeted blankly. Like the slightly awry spotlights swinging around this small hall and never quite fixing on Maguire, the leap to the big time isn't certain. She has that voice – blues through a bullhorn, an operatic vibrato even when she's being delicate. But she's only found one relentless thing to do with it so far.