Jim Cartwright wrote his 1992 play specifically for Jane Horrocks, who burst out of her bedroom-bound chrysalis to shake the rafters as a nightclub singer who could make you feel you were in the same room as Judy Garland, Shirley Bassey or Dusty Springfield.

The transformation seems less astonishing in the sweet and studied performance of 18 year-old X Factor finalist Diana Vickers; she makes LV’s emergence one that is more to do with confidence than brash vocalising talent. But hers is an extremely assured West End debut.

Otherwise, the play stands up well in Terry Johnson’s no-holds-barred production, with its savage portrayal of a skew-whiff working class milieu in a small Northern town on the Lancashire side of the Pennines. LV’s widowed,  alcoholic Mum, Mari Hoff, has set her sights on Marc Warren’s Ray Say.

But Ray, an out-of-time Teddy boy chancer, is moving into artiste management, and when he hears LV singing along with her Dad’s vinyl collection upstairs, he plots her progress in local show business.

The house is riddled with electrical faults, and indeed burns down in the second act, after a series of black-outs, but not before an equally shy and tentative electrician – played by the author’s son, James Cartwright – falls in love with LV at the top of his fork lift truck.

The house is designed on a revolve by Lez Brotherston, allowing full value to the outdoors and rooftop scenes, while the chaotic split-level interior is inhabited by the grotesque posing of Ray as well as the whale-like manoeuvres of Mari’s huge neighbor Sadie, hilariously played by Rachel Lumberg, rounding off her Jackson Five turn with the splits.

Mr Boo, the club manager, is given a nice seedy edge by Tony Haygarth in a precariously applied ginger hair-piece that looks as though it’s been out on the town by itself.

But the real star turn here is that of Lesley Sharp as Mari, whose opening twenty-minute salvo of crass, crude self-absorption is the biggest blast on the West End stage, an amazing performance that is then sustained with brilliance and bravura for the whole, slightly over-long duration.