Brimstone and Treacle, The Bridewell, London

Peter Brook once made an acute point about the kind of showy impersonations of disability that win Oscars.

Peter Brook once made an acute point about the kind of showy impersonations of disability that win Oscars. The trouble with such performances, he argued, is that they are so busy putting on a tour de force of surface tics and spasms that you lose all sight of the human being underneath. I think that, on those grounds, Brook would be delighted by the actress Maria Carson who here plays Pattie, a young woman left brain-damaged and paralysed by a road accident. Without the least recourse to sentimentality, her piercing portrayal lets you see beyond the distressing convulsions and chokings to the unextinguished spirit within.

This performance is the one indubitable asset in Alistair Green's otherwise pedestrian production of Brimstone and Treacle, revived to commemorate the 10th anniversary of Dennis Potter's death. The play has a famously troubled history. The original 1976 television version was banned by the BBC. The bone of contention was the drama's central conceit: that the paraplegic Pattie could be raped back to her senses - in effect "cured" - by a man who either is or believes himself to be the devil. The idea that evil can be the unwitting agent of good is a deeply religious paradox and it's hard to see how a play that is, to a fault, a provocatively inverted parable could ever have been found sickening.

Unfortunately, this revival suggests that the piece, for all its credentials as cause célèbre, has not worn well. Boyish, fulsomely solicitous and a dab hand at domestic chores, Chris Hastings's prissy devil-in-pinstripe-disguise is so much the answer to the prayers of Mrs Bates, Pattie's stressed-out mother, that she might almost have invented him. She's been looking after her daughter for two years and feels so trapped it's as if she's scratching on her coffin lid. To an expressed desire to go out by herself for a change, her charmer of a husband, an oppressive bore-in-cardigan with National Front sympathies, is his usual encouraging self: "Well, nobody would want to rape you".

Flattered by Martin's attentions, Mrs Bates allows herself brief forays into the outside world, leaving Pattie to his tender mercies. Her trust in him is horribly misplaced, and there's an excruciating irony when, on her return, she notes with approval new light in the girl's eyes.

The mother's impercipience climaxes when she asks Martin to join her in beseeching God to restore Pattie. Potter wants to demonstrate that belief can be farcically ill-founded and yet, purely by virtue of itself, bring about a miracle. To hammer this home, though, he has to reduce the Bates couple to caricatures of credulity, on her side, and armchair racism on his - a limitation underlined here by the casting of two actors who are too young to give the roles any complicating presence.

To 7 August (020-7936 3456)