An Education is set in 1961, which was two years before the invention of sexual intercourse, according to Philip Larkin. That’s news to David (Peter Sarsgaard), who has only one thing on his mind from the moment he spots the 16-year-old Jenny (Carey Mulligan) waiting at a bus stop with her cello. He turns out to be a conman and a thief and ends up stealing more than her virginity. By the end of the film, Jenny has lost her innocence as well.

That makes An Education sound like a depressing film about a sexual predator, but it plays more like a fleet-footed comedy. The scenes in which David persuades Jenny’s lower-middle-class parents to entrust their daughter to him, dazzling them with his veneer of Brylcreemed sophistication, are very funny. It’s been adapted from an autobiographical essay by the journalist Lynn Barber and it has the same rueful, sardonic tone. There’s no voiceover, but it feels very much like a story being told from the perspective of the central character looking back at her younger self.

The reason it doesn’t play like a morality tale is because Jenny is largely complicit in her own seduction. She has few illusions about David or why he’s interested in her, but regards it as a price worth paying to escape her cramped, suburban surroundings.

He tricks her parents into letting him take her away on a series of weekend breaks, first to Oxford and then to Paris. She’s bright and adventurous and the innocence she loses isn’t something she sets much store by. It is only afterwards, when she discovers just how much the headmistress of her school disapproves of her behaviour, that she begins to get the measure of her loss.

Jenny’s relationship with David never feels sleazy, mainly because she’s so sexually self-confident. When he broaches the subject of sex, he does so shyly, tentatively, almost as if he were the younger man and she the older woman. She has a down-to-earth, matter-of-fact attitude to sex that is more like that of a contemporary teenage girl than someone born in the 1940s. The only resistance she offers is to ask David to wait until her 17th birthday.

An Education is anchored by a very strong performance from Mulligan. She was 23 when the film was shot, but her self-assurance is so pronounced that it seems to permeate the whole film, infusing it with authority. As you see her skipping from scene to scene, eyes twinkling with mischief, you are in no doubt that a star being born. If she isn’t nominated for an Oscar I’ll eat my hat.

She is surrounded by a stable of British thoroughbreds in the supporting roles. Emma Thompson is particularly good as Jenny’s bluestocking headmistress — it’s as if she’s been growing into this role all her life. Olivia Williams is also strong as an inspirational English teacher who cares more about Jenny’s future than Jenny herself. The scene in which she tries to warn her of the perilous waters she’s swimming in, only to be dismissed with a couple of smart remarks, is heartbreaking.

But the revelation here is Alfred Molina, who plays Jenny’s father. He starts out as a stock comic character, the sort of person Napoleon had in mind when he described Britain as a nation of shopkeepers. Yet as the film progresses he begins to take on more weight and dimension until, eventually, he has become its emotional centre. An Education was adapted for the screen by the novelist Nick Hornby and there’s a scene towards the end, when Molina stands outside Jenny’s bedroom door, asking her to forgive him for not being a better father, that could have been written by Alan Bennett. He fusses about leaving a cup of tea for her on the landing, but beneath such quotidian details there is an ocean of feeling.

Being a film critic can be a dispiriting job sometimes, particularly if you love movies. So many of the ones you have to sit through each week are so terrible. Then a film such as An Education comes along and restores your faith. This is a wonderful, life-affirming picture that deserves all the prizes it will undoubtedly win. I can’t call it the best British film of the year because it’s still only October. But I’d be amazed if a better one comes along.

(12A, 100mins)

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