The hotel receptionist put the early-morning call through to room 227, where a soft-spoken man with a Latin American accent picked up the phone.

"Augusto," I said, "What would you do if you found yourself standing beside Augusto Pinochet's hospital bed? (As all the world knows, the former Chilean dictator is under arrest in a London clinic and may stand trial for genocide).

Boal, the Brazilian playwright, activist and torture victim was fully awake now. "Say to him? Nothing, I don't even speak the same language," he said. "I once visited the museum of the Neanderthal man," he continued, searching for a reference point. "The replica of the Neanderthal man is dressed like a human being, looks like a human being but is a pre-human being, that's how Pinochet is. How can you judge a man like that?" While the Pinochet arrest may not be the direct result of Boal's popular theatre work, his vast experience in stimulating discussion has played an important role in inspiring citizens to resist repression in Latin America.

"The theatre is a weapon and it is the people who should wield it," said Boal, in his ground-breaking Theatre of the Oppressed, a book first published in 1974.

Writer, director and political activist, Boal's work spans four continents, 40 years, and was rewarded with UNESCO's Pablo Picasso Medal in 1992, a lifetime award for his contribution to the arts.

Imagine going out to a play one evening, where the plot unfolds, characters develop and a crisis is presented and resolved. The show doesn't end there however, as the audience is offered a chance to think up a different end to the play. The solutions cannot be offered from the comfort of an audience seat, but require the spectator to come on stage, replace actors and direct the action.

This style, pioneered by Boal, became known as "Forum theatre" and has transformed a rarefied art with little connection to the masses into a powerful tool for change in the hands of workers and peasants.

Boal calls it "the rehearsal of revolution", as the acting out of an attempt to organise a strike becomes the organising of a strike. "The spectator comes on stage and rehearses what it might be possible to do in real life" writes Boal in his latest book, Legislative Theatre, an account of the director's recent activities.

Boal, aged 67, is the son of a baker, who first became a playwright, then artistic director of the Arena Theatre in Sao Paulo from 1956-71, until his arrest, imprisonment and torture by the Brazilian military.

Forced into exile, he went to live in Paris, setting up a centre for the "Theatre of the Oppressed". Boal discovered new forms of oppression in Europe, notably "fear, loneliness and the inability to communicate," which he summed up as "the cop in the head", putting a brake on desire and freedom.

After his return to Brazil in the 1980s, Boal became a deputy in Rio for Brazil's left-wing Workers' Party, (PT). Right now, though, he is at the end of the phone, anxious to debunk the myth of economic stability in his home country, feeling the same anger at the global economic order as he did against the dictators of yesteryear.

"We are in the middle of a long war for the humanisation of the dispossessed," he said, comparing the need to resist corporate imperialism with France resisting the Nazi occupation.

In Legislative Theatre, Boal paints a grim picture of Brazilian society, where all sense of community and co-operation has disintegrated, where "extreme injustice deepens hatred" and business owners offer money for the killing of a street child, with off-duty policemen generally picking up the reward.

In 1992 Boal's Centre of the Theatre of the Oppressed, (CTO) faced shutdown in Brazil, as neither state nor corporate funders was interested in financing an art form dedicated to its overthrow.

Boal and his group decided to go out with a bang and hold a huge fiesta, a tropical wake lasting several weeks, which would bury his popular theatre nucleus with style. However, his best efforts to bury the CTO ended in his election as a vereador (legislator) to Rio's municipal government, representing the Workers' Party, (PT).

"I ran on the condition that we planned to lose," explained Boal, who woke up after the fiesta with a headache, a parliamentary seat, a mandate for popular theatre and a budget to act on it.

He immediately hired all the cultural animators of the CTO, as, for the first time ever, a whole theatre company was elected to parliament. Boal now planned to take the Forum theatre experiment beyond the stage, to create and transform laws.

While he raged against the system, suggesting the chamber be turned into a bingo hall, he also presented and approved his first piece of legislation in November 1995, "The Law of Geriatric Care", which forced municipal hospitals to offer specialist geriatric treatment.

The law was developed by one of Boal's Forum theatre nuclei, the Third Age group, made up of people over 60. The strategy began with an open assembly which identified the most pressing needs of the group. The "Metabolising Cell" then gathered information on the issue and a law was drafted. The "Interactive mailing list" was then put into action, a list of sympathetic lawyers and specialists who might improve the law or spot potential loopholes. The package was presented to the mayor, then put to a vote in the chamber at a session packed with old people watching from the wings. The law was approved.

Boal's four-year term led to the drafting and approval of 13 new laws, all processed through the "legislative theatre" method.

Boal rejects the notion that apathy must prevail in the face of transnational corporate power. "We are now told it's all inevitable, this global market order, so let's surrender," he says, "well so too is death inevitable, should we go and kill ourselves now?" Brazil's dinosaur political class has not forgiven him for daring to take theatre from its rarefied confines onto the street and into parliament. He has been the subject of 10 lawsuits from fellow politicians since entering parliament, with five resolved in his favour and five more awaiting a hearing.

"It's nonsense," he says, dismissing the lawsuits as a clumsy attempt to wear him out.

At the end of November, Boal will take his latest project, the "participatory budget" to the Greater London Council buildings, derelict since Thatcher closed them down. "It's like a trailer for a film which may be completed," he explained. He has invited MPs and the general public to debate and approve public spending in an open assembly.

Could this be the launch of new Labour? It's not surprising that Boal, a Brazilian, will travel to London to give lessons on participatory democracy. The terrible urgencies facing Brazil's poor majority have inspired his work for the past 40 years, demanding creative, collective responses to chronic problems.

Augusto Boal will conduct a public discussion of his work at the Waterfront Hall, Belfast on Saturday at 11 a.m. and at the City Arts Centre, Dublin, on Monday at 8 p.m.