Nine o'clock on an April evening. The streets behind Belfast city centre are wet, chilly and almost deserted. The last knots of late-night shoppers are drifting home. The scene is of a community closing down for the day. But from Central Hall in Rosemary Street come the sounds of laughter, anger, tears. The heart rises. It's just like old times. The man they call the king of community theatre is back in town.

Paddy McCoey, red hair brushed back neatly these days, pale eyes fixing the world with the same old divilment, has the grace to look faintly embarrassed at the grandiose title bestowed on him in publicity bulletins, but he is sufficiently a cute son of his city not to rise to its bait.

McCoey is the original pocket dynamo, the man who, in his own words, "started the revolution" for community theatre and was the driving force behind epics such as The Dock Ward Trilogy, Rebellion and the extraordinary The Mourning Ring, which he directed and devised with residents of the hard-line loyalist estate of Ballybeen in east Belfast.

He has been away from Belfast for the past four years, working in London and Dublin, getting married to Maria - "she's a healer. Appropriate, what?" - having a son, Conor, who is now three, and becoming "settled, calm, happy". Can these be the words of the notoriously feisty rabblerouser of the past? Has he gone soft? A shout of laughter.

"No way. But when I was asked to do this project, I knew I would have to go somewhere in myself, visit places I had been in my head during the Troubles, try to come to grips with this thing of sectarian male aggression, which presumes it has a right to express itself violently. Being sorted, with a home and family, helped enormously in that process. But there has not been a day when someone has not broken down in tears in a workshop session, and I include myself in that."

The sectarian male aggression to which he refers here finds expression among the rival supporters of Linfield and Cliftonville, two Belfast football clubs whose fans traditionally come from opposing sides of the religious divide.

At the heart of Playing For Time are a young boy and his father who go to watch their team every week. The boy is a talented player, has a trial for one of the two big Glasgow clubs and is offered a contract. But that club kicks with the other foot from the boy's family, and when his father hears his son is about to "go over to the other side", it is too much to take.

Flagged as the most ambitious community-theatre project ever staged in Ireland, and one of the biggest in these islands, this multimedia performance is the culmination of the newly formed Community Theatre Association of Belfast's Football Mad project, and the successor to the hugely successful The Wedding, a community play that took the 1999 Belfast Festival by storm.

Playing For Time has been more than a year in the making, emerging through a series of workshops that attracted up to 70 or so people at a time. Several hundred potential participants came forward from community-theatre groups across Belfast. A core of 20 actors was finally chosen, joined by a large supporting cast.

But it is the scale of the piece, to be staged in the round in the massive space of the new Paint Hall Film Studios at the Harland & Wolff shipyard, that puts it in the "biggest ever" bracket.

"It's a dark play," says McCoey. "But it's a great story, and what you will see will blow you away. I'm calling it a live movie. There will be a 360-degree circular video screen, four banks of seating rising up from a circular stage like a bull pit, eight suspended video screens, a trapeze artiste, a soprano, a string quartet.

"The Dublin artist Siobhan McDonald has created some heartbreakingly exquisite imagery, Bill Campbell's music will send shivers up your spine and the whole thing will be lit by Conleth White, who's a genius. Don't even ask me what the lighting must be costing."

Days before opening night, sparks are flying in the rehearsal room. Four women are acting out a scene in a hospital waiting room. A doctor is conveying the worst possible news to a family. It's a difficult set-up, particularly for amateur actors, and lines are going all over the place in their anxiety to get the tone right.

McCoey calls a halt. "Stop letting the lines be in charge! Tell the story." It works. The actors regain their composure and the scene starts again with renewed purpose and momentum. No, he hasn't gone soft.

Watching quietly from the sidelines is the writer William Mitchell, with whom McCoey has worked closely over the past year, devising and developing Playing For Time. Mitchell is a community youth worker on the Shankill Road whose previous pieces have been confined to short monologues and dramatisations. He has reached this point by an unlikely route and, beneath his steely exterior, is plainly delighted to have arrived.

"I was working with an ex-loyalist prisoners' group on an exhibition of memorabilia, linked with Epic [Ex-Prisoners Interpretive Centre] Youth," he says. "It was decided that instead of just putting on a static exhibition, we would try to make a bit more of it. We wanted to do something that would enlighten the public about what it was like to be a prisoner.

"I was asked to write something and came up with three 15-minute monologues, which were performed by an ex-prisoner. They were collectively called Yo, Mister! and represented three decades: the 1970s, the 1980s and the 1990s. They were all on the theme of waiting: a mother waiting for her son, a prisoner waiting for a prison visit and a teenager waiting at the bus stop."

Like McCoey, Mitchell, who is a cousin of the better-known playwright Gary Mitchell, was approached by CAF and invited to join a shortlist of nominated writers. When he was chosen and introduced to McCoey, he felt they could create something out of the ordinary. They are living proof that, for all the depressing public pronouncements and political prevarications to which the Northern Ireland public is regularly subjected, the peace process is moving forward.

A Catholic from west Belfast has come together in friendship and creative partnership with a Protestant from loyalist Rathcoole, with a cast drawn from across the community. The play shows the sophistication developing at the grass roots; it has no flags, no emblems, no overt sectarian allegiances, and allows the audience to make up its mind as to where the characters stand.

"This is an authentic perspective, which developed through the workshops and also as a result of my own contacts with young people on the Shankill," says Mitchell. "I work on a joint youth project, which spans both sides of the Shankill interface. We are like Mormons: we walk the streets and bring kids together. What I find is that many of them are beginning to question the past. They are more concerned with the issues on the streets - punishment beatings, drugs, paramilitary activity - and less and less with the nonsense of the Troubles.

"What we have tried to create is a portrait of a new kind of young person, whose life has the power to redeem others. His family, his friends, the wider community undergo substantial change through their association with him. It is a bleak story, but there is a real glimmer of hope."

Playing For Time by William Mitchell and the company is at Paint Hall Film Studio from Monday to Saturday as part of the Cathedral Quarter festival. Tickets from 048-90232403.

Roisin Ingle will report from the opening weekend of the festival on Tuesday's arts page.