Blackbird, Albery Theatre, London <!-- none onestar twostar threestar fourstar fivestar -->

David Harrower's first and best-known play, Knives and Hens (1995), was a drama of jealousy and sexual power-struggles set in a sparse, medieval society, so austere and limited in language as to seem almost abstract. In comparison, Blackbird, set in the 21st century and dealing with the ever-urgent subject of child sexual abuse, seems almost topical, recent anxieties about sex offenders in schools only making it seem more relevant. But Peter Stein's West End production questions how much this new topicality is an illusion.

The play is set in the functional, garbage-strewn locker-room of a company on a British industrial estate (nicely realised by Ferdinand Wögerbauer's set). Here, Una confronts Ray, with whom she had a sexual relationship 15 years earlier, when he was 40 and she was 12. At first, he assumes she seeks vengeance, or closure, or something, but it is more complex: for both of them their former relationship was more than a simple dichotomy of abuser and victim. She assures him she wanted and valued sex with him; he has never had sexual feelings for any other girl so young. Was their relationship in fact an affair? Were they in love?

Harrower creates an uneasiness about our categories of relationships, a nagging sense that our vocabulary is rarely up to the job. Jodhi May and Roger Allam are assured and disconcertingly changeable - at first, she oozes sexual confidence and righteous indignation, while he is constrained and anxious - but the roles are often reversed, inverted, transformed.

If anything, roles are reversed too often: towards the end of its two hours the play feels a little random and repetitive, and you wonder where it is heading. May goes to leave once or twice too often, and while a latetwist confirms that Harrower isn't trying to replace his audience's easy certainties with his own, it also feels slightly effortful. Here, a final tableau shows Ray and Una wrestling in a car park (with real car and exhaust fumes!). It seems startlingly clumsy for a director of such status, and purely as a spectacle it is ludicrous. But the slippage between violence and sex pulls the focus back a little, clarifying that the play is not about child abuse as such, but about how any sexual relationship can be shadowed by abuse, and how an abuser and a victim can collude. Harrower, it seems, is still tackling the same timeless questions.

To 13 May (0870 950 0920)