THEATRE : Back to Eire, but this time it's blarney

THERE ARE two standard lines about 26-year-old Martin McDonagh, who last year deservedly won an award for Most Promising Playwright. One: it's amazing someone who comes from the Elephant and Castle can write so well about people living in remote parts of Western Ireland. Two: it's amazing someone who hardly goes to the theatre can write so well for it. After seeing his latest play, The Cripple of Inishmaan, you may be forgiven for wishing McDonagh spent more time in Western Ireland, or for that matter, in the West End.

In The Beauty Queen of Leenane, McDonagh presented dead-end lives in a backwater community in present-day rural Connemara. Leenane had suspense, sharp observation and a rich central relationship. In The Cripple of Inishmaan, a play commissioned and produced by the National, McDonagh takes another backwater Irish community where very little happens, this time in the 1930s. Both plays share a enormous facility for comic dialogue and a sadistic pleasure in allowing characters to torment one another. But not much more.

In Inishmaan, the real-life arrival of the documentary film-maker Robert Flaherty to film Man of Aran (1934) on the neighbouring island of Inishmore interrupts the tedium of coastal life. The more ambitious villagers hop across to the other island in the hope of a screen test. (That's news: you need a screen test for a documentary?) The difference between Leenane and Inishmaan is that we don't believe in what happens in Inishmaan: it's too cute. Instead of balancing McDonagh's quirkily logical humour with realistic detail, Bob Crowley's set - which has a soaring backdrop of forbidding cliffs - distorts the windows, doors and shelves in the shop. We meet maidenly aunts with severe hairstyles (Anita Reeves and Dearbhla Molloy), the gossip- mongering Johnnypateenmike (Ray McBride), who trades news for food, and feisty young Helen, who likes to "peg" eggs at people. These bright, comical, faux-naif types wouldn't look out of place if they strolled into Camberwick Green. It's a pastiche. McDonagh invites us to share in the parochialism, the superstition, the credulity and the myth-making, and then mocks it. Having it both ways is admirably post- modern, but in theatre it can end up plain dull.

It is a disappointment, after hearing that the crippled Billy is uglier than a bald donkey, to report that Ruaidhri Conroy is a sweet-looking actor, here making an exceptional stage debut. He does enter with a spectacular limp: his frail body surges up in the air, as his unwieldy shoulders rise and collapse. The resourceful Billy leaves Inishmaan, goes to Hollywood, and later returns. Don't ask how he does this: Conroy is touchingly earnest, but his sincerity masks a sketchy transatlantic journey.

There is one unforgettable scene. Helen, a Celtic version of a St Trinian's girl (a spikily flamboyant performance from Aisling O'Sullivan) suggests to Bartley (an engaging Owen Sharpe) that they play a game called England versus Ireland. Helen is England, Bartley is Ireland. Bartley has to stand still. Then Helen proceeds to break one raw egg after another over Bartley, who looks on disbelievingly, as egg shell nestles in his shiny hair and yolk drips off his chin.

Elsewhere director Nicholas Hytner brings a fastidiously tidy eye to the production. The neatly creased newspaper on the bedstead, the red graze marks on Sharpe's knee, the holes in O'Sullivan's stockings, and the fray on McBride's bandage suggest deliberation to a clinical degree. Inishmaan has none of the messy, damp claustrophobia that gave Leenane its credibility. Here, the aunts totter around tweely like stock characters. A programme note enthuses about the supportive system provided by the National's new-writing policy and links McDonagh to Boucicault, Synge and JB Keane. Yes, and the pub in my local high street says it's Irish too.

Ninety minutes in the company of one actress, who spends the entire time seated on a chair, with only two props, a glass of water and a white handkerchief, neither of which she touches, won't sound like much of a recommendation for a night out in the West End. But Wallace Shawn's monologue The Fever, at the Royal Court (at the Ambassadors), is a remarkably eloquent, precise and searching piece of writing. Shawn wrote the monologue to be performed in any space - in a front room, if necessary - and by either sex. It explores, with the persistence of a heat-seeking missile, the narrator's growing awareness of the gap, or rather the link, between rich and poor, Western democracies and repressive regimes, and lays bare the self-justifying thought processes by which the "haves" come to terms, in their own minds, with the "have-nots". When the narrator of The Fever is arrested briefly, her brush with another, brutal world leaves her unable to return to her previous life.

The excellent Canadian actress Clare Coulter performs Shawn's monologue in a quick, delicate, infinitely varied and questing manner. On the first night, Coulter battled against a motorbike revving for 10 minutes, car horns, police sirens, door-bangings and a helicopter. In their own way these anonymous noises-off were an appropriate counterpoint to this luminously personal piece.

The National's mobile production of Caryl Churchill's Light Shining in Buckinghamshire makes the first of two visits to the Cottesloe, where it looks well out of its depth. A cast of six play 17th-century Levellers, Ranters and Diggers. Mark Wing-Davey's harsh, metallic production has fluorescent lights blinking on and off, slide projections with faint titles and a security camera that shows us on a backdrop what we can already see on stage. There must be a reason for this ... no, can't think of one. The busy lighting technician, standing to the side of the stage in a sea of leads, sometimes has as much light on her deadpan face as the rest of the company. Fussy, self-conscious, distracting, this production left me unconvinced that this piece of cut-and-paste political theatre once had real dramatic qualities. Momentous events, then, and with a pungent period flavour: that of the 1970s .

More gloom: another 1970s play, Beef, No Chicken, at the Tricycle, fails to benefit from Talawa's broad, good-natured revival. The Trinidadian author Derek Walcott couldn't have won his Nobel Prize for this plodding farce.

Theatre details: opposite page.