And yet what else can you do but laugh in the face of the absurd historical bigotry that each side parrots, all of it long since detached from whatever historical legitimacy it may once have had?

Des Dillon's simple play, in which a Celtic supporter and a Rangers supporter find themselves in a police cell during the course of an Old Firm derby, certainly gets a good few laughs out of the situation. That the former really is called Tim and the latter Billy is just the beginning. As well as Dillon's script, new gags are being inserted daily to keep up with events. But just to point up the pettiness of their squabbles, Dillon contrasts these two with the preoccupations of their jailer, who is waiting to hear the outcome of the surgery that his grandson is about to undergo.

Of course the two men, both fathers of young families, struggling to make their way in working-class Glasgow where jobs are scarce and pay is poor, have far more in common than they have apart. And of course in the end, after an initial bout of fighting and some confessions, not least that their own family trees are not quite as pure-bred as their rhetoric would suggest, they discover that truth.

Scott Kyle and Colin Little strut their stuff with a gallus charm in Stephen Cafferty's no-frills production. But in a way, the most interesting thing about this production, staged without any public money by NLP Theatre, is the audience. According to the company, 75 per cent of the audience during the present tour have never been to straight theatre before. Looking round a packed hall and listening to their reaction, responding to every well-trodden refrain as if it was newly minted, I could believe it. They were here to support their respective team.

But if that's what gets them into a theatre and if, at the end of it, the differences between the two sides seem a little less important, that's a respectable achievement for all concerned.

Touring Scotland until June 13, and Northern Ireland in September.

www.nlptheatre.co.uk