Alive from Palestine, Young Vic, London <br></br>Via Dolorosa, Duchess, London <br></br>Witness, Gate Theatre, London

It must be true - it's all in the papers

Last week real life continually threatened to poke through theatrical illusion, making me wonder what I was doing sitting in the dark watching grown men and women caper about. All three plays under discussion tackle urgent, horrible, vital issues of today and raise questions about the nature of theatre itself.

Alive from Palestine: Stories under Occupation is the nearest to agit-prop and comes virtually critic-proof, on a high tide of righteousness. Certainly, Al-Kasaba, under the aegis of its extraordinary impresario George Ibrahim, has suffered grotesque misfortunes: its theatre in Ramallah was attacked, its actors get no wages, and are circumscribed by oppressive curfews and restrictions on movement. Every expense has been spared: the six actors wear street clothes, are barefoot; the set is a moonscape of screwed up Arabic newspapers, the rubble of tired headlines and fruitless analysis from which the cast emerges, blinking. It's a striking, effective metaphor, but it quickly becomes clear that the director, Amir Nizar Zuabi, is no Peter Brook.

It takes a while to align the waterfall of passionate Arabic to the clumsy English surtitles; to adjust high expectations to what seem at first like a collection of slight sketches. It doesn't help that the opening scenes are the weakest, using clichés such as adults pretending to be small children, and walking in slow-motion. It seems authenticity can't always strike the right note. But slowly the production exerts its grip. A young man stands in a spotlight, targeted by a helicopter beam, attempting to communicate with the pilot, to insist: "I'm just like you!" This would be rather trite without the passion of Imad Far'jeen, who managed to infuse his speech with optimism, sadness and confusion: the hedonistic everyman who will, sooner or later, be driven to rage. Later, in "Sharon Stone", Far'jeen plays a movie-mad youth who's heard that Van Damme is shooting in Jerusalem and needs extras. Arriving at the mosque, he misunderstands the shout that "Sharon" is there instead. I wonder if the dismal pun on "shooting" works in Arabic? Far'jeen once more manages to lift his material.

Scrape at the laughter and there's despair underneath: lovers exchange gifts of bullets and gas canisters; children learn to read by chanting "tank", "machine gun" and "martyr". The martyrs cast a strange pall over the proceedings and references to them are oblique and puzzling. There's a hint, for example, that they're not really seen as dead: a child is told he can write to them. I would have liked to learn more about the subject.

David Hare brings a wealth of context to Via Dolorosa and I'm not sure it helps to settle things one way or the other. He visited Israel and Palestine in 1997, talked to people on both sides, and wrote this monologue as a response. He ambles on with the house lights up, talking apparently casually about his diffidence as a performer. This spiel is, of course, carefully scripted, and the show is a bravura display of non-acting.

George Ibrahim makes an appearance; there are comic turns from British Council officials and Sigal Cohen, Hare's sultry, sulking interpreter. Hare's thoughts have been turned into a very effective and squarely structured piece, replete with dramatic irony and counterpoint. His deliberately awkward, pigeon-toed stance and his floppy-puppet gestures suggest an honest realism. And yet his original experiences must have been worn smooth and polished by now: they've become his party piece. Nevertheless, as he weaves his tale, charismatic characters like Ibrahim and his Israeli counterpart Eran Baniel, and Israeli politicians like Benny Begin and Shulamit Aloni, spring to life. (There doesn't seem to be such a thing as an uncharismatic Israeli; or, as Hare's friend Philip Roth says: "Absolute lunatics. They're the maddest people I've ever met in my life.")

In stark contrast, Tamzin Griffith's performance in Witness couldn't be more accomplished. I don't think I've ever seen gesture used more effectively by an actor. Her unnamed character translates the testimony of survivors of the Bosnian conflict for a Swedish therapist. The woman's hands flutter in a half-formed sign language as she explains the difficulty of the job, as though words aren't enough. But the crimes she hears about are not unspeakable, that's the problem; they are unbearable. The mind shuts down at some of the images presented here. (You won't want to eat any "crisply fried" meat after watching this.) She's supposed to be a machine, a translating machine, but in the end she steps out of her role to contact one of the clients, a young man.

It's a paradox that an immaculate performance like Griffith's pushes all thoughts of "authenticity" out of your head. Her immense dignity and authority help to paper over a few cracks in the play. The references to the predicament of the nymph Echo seem mannered and the deployment of atrocities itself begins to look exploitative.

The play's central conceit – that the audience is a professional body here to judge the woman's unethical behaviour – is rather corny, yet it leads to one marvellous moment which fuses the real and imaginary audience. "I don't know if you realise how dreadful it is to listen to these horrors all the time without being able to do a thing," she says. Huge, troubled eyes rake the room. "Or ... maybe you do. I don't know."

Kate Bassett returns next week

'Via Dolorosa': Duchess, London WC2 (0870 890 1103), booking to 31 August; 'Witness': Gate, London W11 (020 7229 0706), to 17 August