THE FRINGE / Man-sized issues: Sarah Hemming reviews plays by Mario Vargas Llosa, David Epstein and Fay Weldon

Mario Vargas Llosa's new play, The Madman of the Balconies (receiving its world premiere at the Gate, Notting Hill) is a splendid example of a successful 'issue play'. It's funny, rich and imaginative, peopled with dotty and enjoyable characters, and while it grapples with intricate moral questions, Llosa lets them arise from a specific situation and explores them through drama as well as argument.

The 'madman' of the title is Brunelli, a frail, quixotic professor who has made it the mission of his old age to preserve the carved colonial balconies of Lima, rescuing them from the developers' bulldozers. But through Brunelli and his minor victories and defeats, Llosa probes around larger issues: asking what constitutes civilisation and whether energy should be spent on cultural relics in any country where people lack the basics.

When we meet Brunelli, he is ruminating gloomily as he prepares to hang himself from one of his precious balconies. From here the play shuttles back and forth, through the events that have brought him to this crisis. We see Brunelli arguing with his arch enemy, the profiteering architect, buoying up his 'crusaders' and fighting his corner against the argument that since the balconies can be seen as the symbol of the conquistadores, to preserve them is immoral.

The play has flaws: a couple of the characters are introduced simply to add to the debate, and the dialogue occasionally clunks a bit. But otherwise it is graceful and witty and offers a fascinating central role in the Prospero- like Brunelli. At first the professor appears noble and idealistic, but as it emerges that he has co-opted his daughter into his mission, his behaviour seems more whimsical and shortsighted. It's a rich role, played with great pathos and intelligence by Peter Eyre. There is a strong performance too from Naomi Wirthner as his daughter, and the central exchange between the two is very moving.

David Epstein attacks his chosen value system - American capitalism - with a different weapon in Exact Change (Lyric, Hammersmith), using farce to highlight his characters' plight. Three no-hopers (Mike McShane, Kevin McNally and Steven O'Shea) in charge of a New Jersey hamburger-joint attempt to get rich quick by investing the profits. But the plot misfires and they find themselves on the run. The comedy (energetically directed by Aaron Mullen) builds to a wonderfully ludicrous finale, where, having bungled an attempt to kidnap a rich dentist, the three wind up in a deserted warehouse, squabbling over the best way to destroy a stolen car.

The situation is hilarious and the non-stop wisecracking script a gift to the fine cast, each of whom finds a different style to convey the desperation behind the comedy. Mike McShane in particular, excels at this, bringing precise comic timing but also a solid sadness to Bompkee. The play is best when it is dealing with the characters' personal problems and the extent to which the system has failed them by filtering the details through the comedy: less successful are the set speeches about dark issues which feel bolted on. But for one-liners, it's hard to better.

Fay Weldon's Mr Director (Orange Tree, Richmond) also focuses on a no-hoper, a 14- year-old 'problem' girl (promisingly played by 18-year-old Clare Woodgate), whom life has failed and the system can't handle. The play debates whether placing her in an isolation unit would constitute therapy, punishment or torture, and sides the disillusioned carers against the indignant liberals. The questions raised are important, topical and absorbing, but Mr Director offers more a set of attitudes than a group of rounded characters, and despite hard work from the cast, remains firmly within the narrowest confines of the earnest 'issue play'.

'The Madman of the Balconies' (071-229 0706); 'Exact Change' (081-741 2311); 'Mr Director' (081-940 3633)

(Photograph omitted)