Whistling Psyche, Almeida, London

It was Kathryn Hunter's childhood dream to play King Lear, an ambition she achieved at the age of 40.

It was Kathryn Hunter's childhood dream to play King Lear, an ambition she achieved at the age of 40. The sprite-like actress has also given us her Richard III and the Old Shepherd in The Winter's Tale. These assumptions of masculine identity were, however, voluntary and temporary, and thus very different from the prolonged male impersonation imposed by cultural constraints on the historical character that Hunter now brings to compelling queer, if mannered life in Sebastian Barry's new play, Whistling Psyche.

Dr James Barry ( c1795-1865) survived an impoverished Irish-Catholic girlhood, moved to England, and was possibly advised by one of her painter-uncle's patrons to disguise herself as a man in order to take a medical degree at Edinburgh University. In effect entering two professions from which her sex was debarred, she joined the army as a physician, serving in various outposts of Empire where, according to the play, her secretly ambiguous status gave her a compassionate affinity for outcasts: lepers, prisoners, the insane. The medical reforms she urged in sanitation predated those of Florence Nightingale by some 30 years. She rose to high rank, but never felt she was given her due, and died embittered, the truth about her sex finally revealed by the charwoman who washed her corpse and found the stretch marks that were testimony to the stillborn child that resulted from her clandestine affair with the Governor of the Cape.

The raw material is fascinating. Always happiest with writing monologues of dense lyricism and rhetorical reminiscence, Barry constructs a scenario that plays to his perceived strengths but that renders the occasion dramatically inert, a fact that Robert Delamere's sensitively shaded production cannot disguise. The author imagines a posthumous, limbo-like situation in which the doctor finds herself in the waiting-room of a spectral railway station (the grand, eerie, fire-lit design is by Simon Higlett). She is so wrapped up in her recriminations that she can't, except in the vaguest sense, perceive the other presence in the room: an ancient Florence Nightingale, whose ladylike asperity and vulnerability are beautifully captured by Claire Bloom.

You know that these opposed types - the unsung rebellious misfit, the icon of Empire who found loathed fame for the very things Barry had pioneered - will eventually discover much in common and end in an awkwardly touching embrace. Until then, the charge between them remains feeble and the situation, despite its latent black comedy, low on laughs.

The monologues, meanwhile, are almost ludicrously overwritten - Nightingale talks of the "wild, broken music'' of the stench in the Scutari wards. Music, though, is the art form that springs to mind when you sit through this work, which feels more like a recital than a play - and a laboured recital at that.

To 12 June (020-7359 4404)