After building a hardcore male fanbase with Fever Pitch (footy versus relationships) and High Fidelity (cool music versus relationships), Nick Hornby went and got all mature on them with About A Boy.

This wonderfully engaging adaptation of Lynn Barber's brief magazine confessional (now a fully fledged autobiography) takes him even further out of lads' mag territory. It's about a girl.

Set in 1962 before Women's Lib and Beatlemania, it follows Barber's alter-ego Jenny (Carey Mulligan), a clever and likeably precocious lass destined for Oxford.

But, conscientious as she is, Jenny longs for more than the life mapped out for her by her blustering dad Jack (Molina), her unfulfilled English teacher (Williams) and pious headmistress (Emma Thompson).

Then, while standing in the rain with her cello, up rolls a knight in a shining motor.

Wealthy, charming, sophisticated, and clearly as shifty as a cat next to a goldfish bowl, David (Sarsgaard) sweeps Jenny off her soggy-stockinged feet.

More importantly, he wins over her parents in no time. Then it's off to the West End and beyond for culture and high living with his friends Danny (Cooper, a late replacement for Orlando Bloom) and the adorably dim Helen (Pike).

Only when the wheels come off does Jenny realise how much she has to learn.

The potential for histrionics is huge. Thankfully, writer Hornby, Danish director Lone Scherfig and the consummate cast ensure that nothing is overplayed, from the presentation of the period to the emotional ups and downs.

Molina and Pike steal their respective scenes as the blowhard and the bubblehead, while the American Sarsgaard nails his British accent in his trickier part by making David less of a pervy old cad than a feckless opportunist.

But, emerging from the shadow of her big Pride And Prejudice sisters Pike and Keira Knightly, it's Mulligan who proves the real draw.

Twenty-two when the film was made, she strikes a perfectly adolescent balance between dimpled cheek and unchannelled wisdom in a breakout role reminiscent of Emily Lloyd in Wish You Were Here. It's like somebody rediscovered Samantha Morton with a sense of humour.

The film's a gem - and her performance is an education in itself.

Elliott Noble