The Curious Incident Of The Dog In The Nighttime

It's been killed with a garden fork and when he's questioned by a policeman at the scene of the death, it becomes clear that Christopher is not your average 15-year-old.

He's awkward and uncoordinated and his responses range from the abrupt to the excessively detailed. When the policeman takes him by the arm, Christopher strikes him. The mystery of the murdered dog becomes a hinge on which we come to understand the autistic Christopher, played by the excellent Luke Treadaway, along with his family and their life with the condition.

How to tell the tale of one boy on the autistic spectrum, without generalising about autism as a whole, is the difficulty Haddon faced when writing the book, prompting him to explain that this is not a story about disability but about difference.

That's how he hoped the play might be approached and there's no doubt that Stephens's adaptation, first seen at the National Theatre, honours the novel's spirit while managing to translate Christopher's internal narrative into a multi-sensory experience which is excelllently directed by Marianne Elliott.

This enables the audience to gain an understanding of what it is like to be Christopher and what it is like to be around him.

Bunny Christie's abstract geometric set outlines the neat grids of Christopher's mind and Paul Constable's arresting use of light heightens the protagonist's disaffected nature and the distress he experiences when his routine is disrupted.

That combination, and the choreography by Frantic Assembly accentuating the collision between Christoper's reasoning and reality, propels the play's astonishing trajectory from Swindon to Willesden.

In an outstanding cast Christopher's teacher Siobhan (Niamh Cusack) doubles as narrator, an especially powerful device in revealing the selfishness of all involved, including his mother (Holly Aird). Sean Gleeson plays a marvellously browbeaten father and his relationship with his son is touchingly fraught.

It's a virtually faultless production but there still remains something amiss - perhaps the unwieldy length of the play in its attempt to stay true to the book or the showbiz garishness of Christopher's post-curtain demonstration of Pythagoras's Theorem.

Or maybe it is the cumulation of all the characters like Christoper we've met through film and literature which leaves one wondering whether every autistic child is, by definition, a master of maths.

Runs until August 31. Box office: (O20) 7452 3000.