Scenes From The Big Picture, National Theatre, Cottesloe, London, ****

A colourful slice of Belfast life

An award should be given to whoever conceived the idea of teaming the up-and-coming Northern Irish dramatist, Owen McCafferty, with the veteran director, Peter Gill. McCafferty may hail from Belfast, and Gill from Cardiff, but there are clearly strong creative affinities. Gill's flair for getting inside the daily lives of the denizens of the Welsh capital in a play such as Cardiff East is matched by the intuitive understanding and humane insights that McCafferty now brings to bear on the inhabitants of Belfast.

The playwright made his mark with Closing Time, one of the best of last year's Transformation season at the National. A sort of "Long Night's Boozing Into Day", it stayed firmly put in the one seedy Belfast pub. Scenes from the Big Picture, by contrast, hops around, interweaving stories almost like a soap opera, as it presents a panoramic picture of Belfast existence. It takes a "life in the day of" approach, and if ever there was a justification-in-action for public subsidy of theatre, it is the cast of 20 superb performers that this production has thereby been able to afford.

The show presents a community, and the production brilliantly reinforces this by its own communal procedures. When not themselves acting, the members of the cast sit and watch on a row of chairs at the front of the stalls, leaping up to effect the scene-changes – from pub to corner shop to meat plant – on Alison Chitty's striking blue set. These changes are, in themselves, little dramas of urban choreography, played out to the sounds (alarms, pneumatic drills) of street life.

The Troubles are an issue in these people's lives, but Scenes – where the sectarian divide is scarcely mentioned – is not an issue-play. Instead, its focus is the private lives impinged upon by politics, and the tone is often tragicomic in a way that's reminiscent of Sean O'Casey. On the day of their father's funeral, two feuding brothers are sponged off for drinks by a couple of topers who barely knew (still less, loved) their dad. The disreputable comedy of that darkens, though, when the brothers unearth a cache of arms on the paternal allotment.

It's not the only thing uncovered on this day. Theresa, the manager of the meat plant, is having difficulty paying the workers, and the spectre of short-term contracts looms. Then the news comes that the police have found the body of her long-missing son. She had kept her marriage together by just buckling down; now the scab on her grief is torn away.

The stories intersect in droll and sad ways. The man who runs a corner shop, who is terrorised by druggie vandals, believes that Belfast's cab drivers are all dealers. So it amuses the man who actually is a dealer, to give the shopkeeper's wife a lift to the hospital in a car stuffed with drugs.

It would be invidious to single out particular performers. They are all excellent, right down to the youngest. Usually, when a cast has to watch the show as well as act in it, you feel it must become a bore for them. Here, though, you reckon it must be one of the perks of the job.

To 21 June (020-7452 3000)