Kin, Royal Court Theatre Upstairs, London

Enid Blyton must be gyrating in her grave.

It would be hard to think of anything less like Malory Towers than Kin, EV Crowe's jolting low-down on life among the 10-year-olds at a girls' boarding school in the 1990s. Her gym-slipped mites turn the air blue with relentlessly foul-mouthed talk, as though in contention for some David Mamet Memorial Cup.

The competitive bitchiness with which schoolgirls mask vulnerability may boast a long ancestry, but exposure to the heartless values of trashy glossies seems to have given the process an added cooler-than-thou viciousness. One pupil dares another to knock on a male teacher's door and tell him "you want to do 'position of the fortnight' out of More magazine and that you want him to rape you." In Jeremy Herrin's witty, bleakly atmospheric production, the shock value is heightened by the fact that these characters are played by girls who are barely older.

The play focuses on the relationship between a pair of dorm-mates. The outwardly tougher Janey (Mimi Keene) persecutes and is possessive about the cleverer but less developed Mimi (Ciara Southwood). So when the latter wins the part of Proctor in a production of The Crucible, Janey jealously retaliates with crass insinuations that rival Nina (Fern Deacon) is Mimi's "fuck buddy".

The choice of play reflects the hothouse ambience of gossip and denunciation that suffuses Kin and it allows for some hilarious generation-whatever descriptions of Arthur Miller's hero. But Crowe's own distorted mirror of its plot – involving a hysterically prurient teacher and forced confessions – manages to feel both too slight and excessively melodramatic. Where the play shows real talent is in its acute ear for callous school lingo and in the quality of its observation.

A promising Royal Court debut for the author.

To 23 December (020 7565 5000)