Mean Girls has all the trappings of a standard teen comedy: designer clothes, a moral message and Lindsay Lohan. But this perceptive picture is both surprising and funny - and teenage America takes a right mauling. High school is presented as a jungle, where newbie Cady (Lohan) will struggle to survive. She makes mates with grungy outsider Janis (Lizzy Caplan) and is encouraged to befriend the "plastics" - a gang of fascistic fashionistas led by Queen Bee(atch) Regina George (Rachel McAdams). Once 'in', the idea is to destroy the clique, but there's an appeal to becoming part of it...

"WITTY, BARBED, AND, CRUCIALLY, TRUE"

School, they say, is the best time of your life. Anyone who considers this a depressing lie should appreciate this caustic comedy. The screenplay, by Saturday Night Live writer Tina Fey (who also co-stars as Cady's teacher), is based on US bestseller Queen Bees And Wannabes: Helping Your Daughter Survive Cliques, Gossip, Boyfriends And Other Realities Of Adolescence (catchy title). And while the story may be fictional, the setting feels authentic. Fey clearly remembers how cruel kids can be, and the crippling desire to be cool at school - whether through jargon, dress-sense, or doing someone else down. The script is witty, barbed, and, crucially, true.

Lohan is perfectly cast as the innocent seduced by the system, while McAdams is a star in the making, giving pep to a part that could have appeared a stereotype, playing the Machiavellian blonde with convincing malice and an impressive lack of actorly vanity.

The pacing is slightly uneven and the conclusion a little too cosy, but even when it slips into self-help-speak there's still a splash of sarcasm. Mean Girls is far from perfect, but it has brains beneath its glossy, vacuum-packed beauty. Clueless meets Heathers: every teenager should see it.