THEATRE: Fun and losses on our summer holidays

This month, the Bush marks 25 years of staging new plays with a book, a bash and - best of all - a debut play by a writer in her early twenties. It was sent it in as an unsolicited manuscript and the Bush couldn't have asked for more. Caravan by Helen Blakeman is candid, contemporary and funny.

It also takes place in the most cramped acting conditions I can recall: inside a holiday caravan in Towyn, North Wales. The cross-section we see fills two-thirds of the stage. In a stunning opening, 15-year-old Kim (Samantha Lavelle, making her stage debut) brings back Mick (a lean and hungry Nick Bagnall) to the caravan. He brings two mint choc-chip ice-creams, and, inspired perhaps by Haagen-Daaz, she loses her virginity in a randy comic encounter which becomes more complicated than when it begins. Next, Mick starts seeing Kim's elder sister Kelly (Emma Cunniffe). Both girls end up pregnant and Caravan, which has the gripping air of a soap (Blakeman was once an actress on Brookside) is on the move.

The sexual betrayals are paralleled by political ones. Kelly and Kim's mum, Josie (Elizabeth Estensen) has a new boyfriend Bruce (Pip Donaghy), a Liverpool docker who loses his job. Mick gets his first ever job by becoming a scab. Blakeman doesn't obtrude her views on these tangled relationships (there are too many deceits taking place in this one caravan to list). The result is a refreshingly frank portrait of teenage life, hilarious and bleak by turns. Gemma Bodinetz directs a first-rate cast. Something to celebrate.

Writing in this paper, David Nicholson-Lord once described environmentalism as "the most significant innovation in political thought of the 20th century". If that's so, it's one which has largely passed British theatre by. The environment is one subject (childhood is another) that playwrights don't quite know how to handle. At the Bristol Old Vic, Nick Darke's The Man with Green Hair takes the outbreak of aluminium poisoning in the West Country's water supply as the premise for 90 minutes of farcical antics. This isn't the same as farce, which is more strictly regulated.

When the tap water in the office of a pollution-control department starts looking like Ribena, Patsy the lab assistant (Emma Bown) thinks they ought to prosecute. All they need is a victim. Her boss Milt (Mike Shepherd), suicidal because he has just lost his home in the High Court to his ex-wife, agrees to be the guinea-pig. He soon has a series of complaints: "me dick's gone slack", his toe-nails fall out and his hair turns green.

Which is about as green as the show gets. The Man with Green Hair comprises a madcap series of events, one-off ideas and larkily surreal touches. A bulldozer, helicopter and tanker lorry all make appearances, but as vehicles go, this isn't one for cogent environmental argument. A partisan squib, Green Hair is held together by our shared dislike of privatised water companies, memories of the Camelford incident in Cornwall and Darke's quick and appealing ear for dialect (eg, "he don't live up downhill any more"). The play never seems very true in its specifics, so for all its energy, it is never very funny. The Old Vic's Andy Hay gamely directs.

The Dublin director Ben Barnes has led the way in re-interpreting the plays of John B Keane (who wrote The Field). In the wake of Martin McDonagh's prolific output of mock-Irish plays, these brooding stories of rural backwardness and meanness have a slightly tarnished air. It's like switching from Rory Bremner doing Tony Blair to seeing Tony Blair do himself (pretty, similar, but without the jokes). In Sive, written in 1959, an uncle and aunt arrange the marriage between their orphaned niece Sive (Catherine Walker) to a 70-year-old pink-faced farmer: they'll get pounds 200 for it, and the limping, bearded fixer (Simon O'Gorman) gets pounds 100. Barnes has assembled a strong Irish cast to convey the melodramatically oppressive household. But the old lady in the black cardigan with her hair in a bun, the staunchly malevolent aunt stomping around in socks and boots, the tinkers dropping in, drinking porter and singing folk songs, have all become over-familiar figures. Ireland has one of the fastest growing economies in Europe (almost an eight per cent rise in GDP in 1995-96). Let's see something that reflects that.

Peter Hall's Old Vic season had its final opening this week. What we have seen is 12 completely different plays being staged - on modest design budgets - on the same imposing stage with the same deep auditorium; and they have often struggled to fill the space. Chris Hannan's Shining Souls, which premiered at the Traverse in 1996, is still funny (if not quite as funny as it was then). Hannan has an exuberant gift for rhetoric, and lines up a delightfully off-beat collection of Glasgwegian characters, led by the engagingly indecisive Alison Peebles, caught on her wedding day between two guys called Billy and a loquacious scrounger. Shirley Henderson is dangerously leery as the pent-up daughter, and Brian Pettifer hilariously down-to-earth as the harassed clergyman who recognises that for this bunch, 10 commandments are way too many: "pick one and try and stick to it".

It was an incongruous sight, seeing the courtroom for the War Crimes Tribunal at the Hague sited next to the subway exit for Broadway and West 42nd Street. For the National's platform performances of Tricycle's production of Srebrenica took place on the Olivier in front of the set for Guys and Dolls. In Nicolas Kent's eye-opening production - which ought to tour the whole of the UK - the roles of the witnesses and lawyers were superbly understated, conveying the horrific through the humdrum - as the cast paused to check facts in notebooks or to ensure the headphones were working. The testimony of the Croat (Jay Simpson) who shot Bosnian Muslims for the Bosnian Serbs was unforgettable: he would simply have been shot, he says, if he hadn't shot the others, and even then it wouldn't have made any difference.

In the discussion afterwards the panel (which included Martin Bell and Paddy Ashdown) had been promised an "ambient" microphone. It wasn't on and half the audience couldn't hear. As one panellist after another made the point of how hard it had been to get across the message of what was happening in Bosnia, the sound technicians at the National unwittingly dramatised their point.

'Caravan': Bush, W12 (0181 743 3388), to 13 Dec. 'Sive': Watford Palace (01923 225671), to Sat. 'The Man with Green Hair'": Bristol Old Vic (0117 987 7877), to Sat. 'Shining Souls': Old Vic, SE1 (0171 928 7616), to 1 Dec. 'Srebrenica': Belfast Festival (01232 665577), Mon-Fri.