Here the focus is on a less frequently investigated bunch - the Roman Catholic upper class, exemplified by the O'Donnell clan who have gathered in the decaying family mansion for a wedding that is pre-empted by a funeral. The great-grandfather had been Lord Chief Justice. The tyrannical father, who is dying upstairs, was a simple district judge. His son is a failed solicitor. As Eamon, the local working-class boy who married into the dynasty, jokes: the only way a future O'Donnell could keep up the family legal connection would be as a criminal.
Ignored by their Protestant counterparts, removed from the mere "Irish", and indifferent to the Catholic Civil Rights movement over the border, this class is now on its last legs, brought low both by inner deterioration and by the levelling economic forces that are pushing young Claire (Marcella Plunkett), a depressive pianist, into marriage with an elderly widowed grocer.
The production skilfully sustains the play's meditative, tragicomic mood. And while you can't imagine Chekhov employing as crude a device as the visiting American Prof (Stephen Boxer), who is researching a study of the Catholic "aristocracy", there is something genuinely Chekhovian in the mix of objectivity and compassion with which Friel views this dying breed.
Gina McKee is too doggedly dour to touch the heart in her portrayal of Judith, the sister who has had to martyr herself to the management of this crumbling household. But Andrew Scott is outstanding as Casimir, the misfit brother who has escaped to (possibly invented) marriage and fatherhood in Hamburg. He's nervously hyperactive, liable to buckle in terror when his bedridden father's voice is heard through the baby-alarm system, and concocts wild fantasies about the family's cultural history ("Grandfather told Balzac to shut up, and Chopin said...").
It's ironic that the character who most resents the presence of the fact-finding, myth-puncturing Prof is abrasive, working-class Eamon (an attractive, if perhaps too genial Peter McDonald). He knows that the Big House appeals to "all that is fawning" and ripe for colonisation in the peasantry. And yet its loss leaves him feeling more bereaved than the others - a revealingly divided reaction in a richly ambivalent play.
Until 25 August (020-7452 3000)