THEATRE / The missing link: Jeffrey Wainwright on Poison Pen in Manchester

Ronald Harwood's new play looks and sounds like a whodunit - there's a clunkingly solid set, threatening letters, a country cottage, a revolver, and a policeman comes on at the end - but in fact he has contrived a different genre, one we might call the 'whosit'. 'Whosit?' is of course a far more complex question than 'whodunit?' With the latter, by the time the policeman's on, we have all the revelation we crave, but in a 'whosit', the interesting questions only start with nominal identification.

So we meet a man called Eric Wells (Tom Courtenay) and learn a lot about him very quickly. He lives in 1930 with his male lover, Larry; he is a notable music critic; he is in fear of his life. This is on account of the letters he is receiving from a composer, Peter Godwin, whom he has accused in print of plagiarism. Faced with Godwin's publisher demanding a retraction on pain of legal action, Wells appears principled, stiff-necked and passionate. Larry, meanwhile, painfully jealous, believes Wells to be having an affair with Godwin's young mistress Juliette. Convinced that if Wells reviews Godwin's next recital there will be a catastrophe, the publisher determines to discover the truth. Does Godwin's work mimic Delius? Are Larry's fears right? Does the high seriousness conceal the old worm of sex? Or is there another kind of jealousy at work, that of the critic for the creative artist? What is the truth? Who is Eric Wells?

In fact the truth is decisively simpler than any of these alternatives, and diminishes the possibilities of Harwood's themes. These are a brew of the desperate divisions flowing through Wells: sexual ambiguity, hatred and self-hatred, the costs of art, pacificism and violence, and how all these things might be connected. But in the first half they are only rehearsed, mainly by Wells, and do not seem more than a top-dressing of ideas. In the second half, after 'all is revealed', Harwood writes a display of Wells' dementia rather than a visitation to his inner conflict.

As a piece of character creation, Tom Courtenay's performance is very good. His distinctive mannerism of raising his tone at the end of a sentence, often stressing the last syllable even of a word like 'cottage', works here to convey an arty affectation but with a saw-tooth of nervous aggression. In support, Rhys Ifans deepens the seemingly shallow Larry as the tone darkens, Emma Amos slowly opens the wound of Juliette's damaged sexuality and Michael Simkins furnishes an interesting dignity for the stolid publisher. Harwood directs.

At the Royal Exchange until 26 June (Box-office 061-833 9833)