What exactly is fringe theatre? Although this may seem an obvious question, it nonetheless provoked lively confusion at a seminar entitled "Is Fringe the Main Event?" at Limerick's "Unfringed 2001" festival on Saturday.

With three of the four originally-billed speakers (playwrights Enda Walsh, Gina Moxley and Conor McPherson) not present, playwright Ursula Rani Sarma was joined instead by writers Mike Finn and Michael Collins. There was no official representative from the Dublin Fringe. The discussion, chaired by John Tiffany, literary director of Edinburgh's Traverse Theatre, was enjoyable yet failed to get to grips with the many issues relating to fringe theatre in Ireland.

At one point, however, a heated debate did break out among the audience. One audience member called the Edinburgh fringe "hideous" and full of "absolute rubbish", while another argued that there should be no distinction between fringe and mainstream ("good is good and bad is bad!"). Conclusions as to what constituted fringe varied, with some audience members feeling it was defined by class, and others by money.

According to "Unfringed" director Liz Culloty, there is "no social distinction" between the audience for the festival and the Belltable's regular audience. She added, however, that "there is an audience that appears for `Unfringed' that doesn't appear again for another year".

It is this audience, which does not regularly go to the theatre, that defines the fringe for writer Michael Collins, whose first play, The Hackney Office, was recently premiered by Druid Theatre Company. According to Collins, the fringe audience is "more up for it . . . more interactive".

Mike Finn, whose play, Pigtown, was one of the popular successes of last year's Dublin Fringe Festival, agrees: "It changes audience's expectations - and makes theatre possible for those who don't have much money."

The problem with discussing fringe theatre in Ireland is that the form is still primarily associated with Edinburgh in many peoples' minds. Vast, rambling and random, the Edinburgh fringe is a world unto itself. The Dublin and Limerick fringes are minuscule in comparison to Edinburgh (Dublin stages less than a 100 shows, a fraction of Edinburgh's thousands).

But the Edinburgh fringe has, in a sense, become a victim of its own success. Originally set up to encourage experimentation and innovation, according to John Tiffany, the Edinburgh fringe has become so commercial that theatre companies "can't afford to go there. The fringe has become mainstream".

Certainly there has been much debate this year about the Edinburgh fringe being overrun by commercially produced stand-up comedians grooming themselves for that possible sitcom pilot on Channel 4 and would-be TV presenters who are not interested in theatre and who cannot act, but who will do anything to be seen by the television producers who prowl around Edinburgh every year. John Tiffany admits that even the Traverse sees fringe time as its "panto season" and hikes up the ticket prices to match.

Conversely, under the controversial management of Brian McMaster, the "official festival" (the Edinburgh International Festival) has gone from obscure to more obscure, leaving a string of box-office failures in its wake (The Barbaric Comedies, co-staged with the Abbey Theatre, merely being the latest).

In Ireland, fringe is still a relatively new idea, which took root at the Dublin Fringe Festival in 1994. Since then, there has been a radical growth in both its quality and its audience. Recently, the Dublin fringe has branched out to include forms for which there is no equivalent at the Dublin Theatre Festival - for example, visual arts.

"Unfringed" in Limerick is even more curious, there being no "official" festival of which it is the fringe. Director Liz Culloty admits to an ambivalence about the term that is reflected in the festival's name: it is fringe and yet it is not, for the shows are carefully selected.

"`Unfringed' means we pick the shows; we provide audiences with an opportunity to see shows they might not otherwise see," she says.

But then, are the Dublin and Limerick fringe festivals really fringe at all? With individual programmers and a selection policy, both constitute festivals rather than fringe festivals.

This year, the "Unfringed" event branched out into commissioning - a new and, as Culloty admits, as yet experimental move, providing yet another possible function for the idea of fringe: as a training ground. Young playwright Ursula Rani Sarma, this year's Irish Times/ESB theatre bursary winner, admits that she "fell in love with theatre at the Edinburgh fringe", and her new play, Gift, is the central offering of "Unfringed".

Perhaps not a total success, the production is energetic and full of promise, and Sarma proves herself a name for the future. More importantly, the opportunity was given to an accomplished young writer in the early stages of her career to learn and refine her craft in front of an audience. This could be the start of an exciting and possibly crucial future role for the fringe in the Republic.

Fringe theatre has many functions and many more definitions, and perhaps this is its point. Its primary role is providing an opportunity to contesting the dominant artistic trends of the main stages.

In Edinburgh, this means commercially produced stand-up comics and lots of people rushing about the streets in chicken costumes. In Dublin, it means younger companies can take a chance on a show with the support of a larger festival. In Limerick, it means commissioning young playwrights and profiling shows from the rest of Ireland.

So far, Dublin and Limerick have avoided the pitfalls of Edinburgh by remaining small-scale, exclusive and under the artistic control of individual programmers. But neither have Edinburgh's energy, freedom or random craziness . . . or its sheer amount of "absolute rubbish".

Perhaps that's a good thing. But the worry is that as Irish fringe festivals grow in popularity, they will just become mainstream institutions.

The power of fringe is the power of possibility. And, to a certain extent, that requires a lack of definition. The fringe may be where it's at - but it should never be the main event.

"Unfringed 2001" continues until Saturday. For information, phone 061-319709