Aristocrats, NT Lyttelton, London

The aged patriarch, District Judge O'Donnell, is still making his presence felt, barking out orders. However, he's bedridden upstairs and only heard through a baby-monitor. His voice from on high is obviously senile, relaying his delusions of almost God-like grandeur. Meanwhile, wandering through the library and out onto the lawn, his offspring are mentally shaky and financially on the skids. Marcella Plunkett's still-girlish Claire is about to get married and plays a stream of lovely Chopin waltzes and sonatas on the piano - yet, underneath that, she is a manic depressive and lost soul on sedatives.

Her older siblings are thwarted as well. Dervla Kirwan's bruised Alice starts drinking herself into the ground, while her husband, Peter McDonald's Eamon - whose gran used to work at the "big house" - oscillates between jocular mocking and a romantic love of the old place and all three upper-crust sisters. Gina McKee's Judith struggles to ignore his insistent questions about why she didn't marry him. As for their brother, Andrew Scott's Casimir listens with ecstatic nostalgia to the Chopin and tells Tom wonderful tales about Yeats keeping watch for ghosts and the lardy Chesterton falling over (while doing an impression of Lloyd George and leaving his permanent indentation in the fender). Yet Casimir is always twitching neurotically and collapses in infantile tears.

Certainly there are poignant, tense and humorous moments here, especially when you realise Stephen Boxer's snooping Tom is being fed a load of mythologising blarney - teasingly reflecting Friel's own mix of historical and invented scenarios. Aristocrats is a warmly humane and intelligent study of Irishness and unhappiness, class and family relations and fantasising. As well as strikingly foreshadowing Stoppard's Arcadia, this tragicomedy is rich with Chekhovian echoes and sometimes has a lovely, meandering, life-like drift to it. The closing act is beautifully orchestrated: a serene, haunting diminuendo.

However, prior to that, Cairns' production often feels dull and washed-out. Letting him design as well as direct was a mistake. Cairns' set is a hotchpotch of styles: a watery outline of a huge tree coupled with a naff and incongruously detailed painted view into the library, plus a spread of real scruffy grass. There's one completely redundant scene-change which took so long on press night that half the audience thought it was the interval. The vaulty space also swallows the cast's voices. Beyond that, more sharply focused work needs to be done on the characters' cross-currents of attraction and aggression. Often precious little seems to be going on dramatically - though the play is partly to blame for that. McDonald is doing his best to be a hub of confused anger and tenderness, but others appear aimless and McKee certainly isn't stretched, playing outward composure with a few flashes of pain and frustration. Friel wrote his much more brilliant historic drama, Translations, just one year after this in 1980, and the good news is the National is staging a touring production of that in September.

k.bassett@independent.co.uk

To 13 October, 020 7452 3000