JAMIE Bell, the actor who will always be remembered as a child, has made a film about becoming an adult.

It's called Hallam Foe, and where once Bell danced his way out of the dales as the balletic Billy Elliot, he now leaps across the gothic rooftops of Edinburgh at night, spying into bedrooms.

Directed by David Mackenzie from the book by Peter Jinks, Hallam Foe is a coming-of-age story told like an adult fairytale.

It's about the voyeuristic adventures of its troubled protagonist and Mackenzie draws us into a netherworld caught between adolescent fantasy and adult reality.

From this you can sense Bell's need for us to consider him as a serious young man.

The English actor has acquired an equine nobility of face and the graceful, muscular physique of a dancer. But in Hallam Foe, he really could be some kind of simian.

Hallam spends a lot of time clambering about a treehouse, can scamper up a lamppost out of sight of chasing bobbies, and later lives in the garret of an Edinburgh clock tower keeping close watch on a young woman who looks like his dead mother. His feet hardly touch the ground. But even more skyward are Hallam's psychosexual issues which would have had Freud running for cover.

Hallam, who spends a lot of time on his own, likes to wear his mother's dress and sport an earring she once owned. He also spies on strangers through their windows and spends most of his time by day in his treehouse retreat journalling his evening enterprises. The teen is also determined to upset his wealthy architect father (Ciaran Hinds) and his new wife Verity (Claire Forlani).

Forlani makes for a very unusual stepmum. She has a bewitching beauty that confuses poor Hallam:

what could be worse for a troubled adolescent who thinks his wicked witch of a stepmum killed his mother than also to want to go to bed with her?

When she discovers Hallam's peeping Tom diaries, she blackmails him to leave. The tension between them gets so taut you would think they are about to snap into each other's arms. And then suddenly, they are in each other's arms. How did this happen? Where once Jamie Bell enamoured himself with every mammy in England, here he is getting off with his stepmum, while he later tangles with a young lady he fantasises is his dead mother. Sophocles called his version Oedipus Rex.

Hallum's complex is so monstrous and aggressive Mackenzie could have called this Oedpius T-Rex.

The other woman in his life is Kate (Sophia Myles). He spots her while living in exile on the rooftops of Edinburgh. (By night the city is beautifully cinematic and Mackenzie creates a Dickensian atmosphere among its shady, narrow streets and gloomy skyscape. ) Kate's face is round and angelic, a blonde fairy princess who looks uncannily like the photo of his mother in her passport he carries around.

Hallam works his way into her life: he follows her and blags a job as a porter at the hotel where she works; he watches her affair with a married man through the roof window of her apartment. Later, he outmanoeuvres this man's affections; soon, she starts to have feelings for young Hallam.

It is the kind of story that could have been filmed perhaps by Lynne Ramsay, recalling her own very internalised films Morvern Callar and Ratcatcher. Mackenzie revels in complicated relationships, but unlike his sombre Young Adam, this has dark humour and sprinklings of magic.

Hallam's feral unpredictability is the best thing about it: while we are disturbed by his obsessions, we are also enamoured with his cunning, and Bell's physical presence captures the role. But Hallam Foe leaves us wanting.

For all its joys and its wellcrafted fairytale duality, the story is a ruse: it crashes down to earth when you realise it is just another Salinger-esque coming-of-age story. It plays to form while the rest of the film plays to our imagination. Hallam must eventually come down off the rooftops and the film seems too eager to resolve his problems. Which is a shame, because the story demands something a bit more special. I'm with Hallam on this one: his world is a screwy place, but it's a more endearing place to be.