Comics doing theatre is a recent staple of the Edinburgh Fringe: 12 Angry Men, One Flew Over The Cuckoos Nest, The Odd Couple, all familiar works successfully revived for previous Fringe runs. Now Phil Nichol, who was in the cast of the first two, has set up the Comedians Production Company to nurture similar projects. And guess who gets to play the lead in their first show

Talk Radio is different from its forebears in that it's not such a well-known play, despite a cult film adaptation, nor is it much of an ensemble piece. This is all about the lead character, a pioneering phone-in host called Barry Champlain, the charismatic, blunt and intelligent voice of a controversial late-night show.

Nichol may be the producer, but he's also well-placed to play the proto-shock-jock. His previous roles, not to mention his stand-up, have proved he can be an electrifying performer who can brutally demand attention. And boy, does he need to, as this is one of the most visually dull plays around.

On stage, Champlain is flanked by his call screener Stu, played by Stephen K Amos, who has very little to do, and his assistant Linda (Tiffany Stevenson) who has even less. Instead, the drama unfolds through the untheatrical medium of phone calls, with the supporting cast of Mike McShane, Will Adamsdale, Tony Law and Tara Flynn showing plenty of verbal dexterity in supplying all the callers from an offstage hideout. And what a lot of callers there are, too ­ no wonder the play far outruns its advertised 75-minute slot.

Champlain sees himself a modern philosopher, an eloquent voice of reason in a rotten country going to the dogs. Only he has the answers ­ not in some namby-pamby tree-hugging form of liberalism ­ but tough, realistic solutions. He is the only true way. Many of Champlain's callers hate him, many more idolise him. And for those believers, their phone calls to him are prayers to be answered.

Eric Bogosian wrote Talk Radio in the mid-Eighties, before the airwaves were awash with moronic shock jocks. Now it's a period piece in which Champlain is a one-off, a taste of things to come. That radio has changed mean a modern audience might no longer be so interested in his rudeness to callers or the virulence with which he expounds his views ­ that's no longer out of the ordinary ­ although other aspects of the character, such as the extent to which his exalted celebrity defines his personality, are still relevant.

The night we're tuning in is the last before Champlain is syndicated coast-to-coast, so the sponsors are listening in and the pressure's on. Though even without national exposure it already seems as if we've got callers representing every aspect of American life; from the timid woman entombed in her home by her morbid fear of every danger from microbes to foreigners (which pretty much sums up the news agenda of the modern-day Daily Mail); to the liberals who get a warped validation from their false concern for the suffering of others, and of course, the unedifying line-up of loudmouths, drunks and bigots.

One caller, especially, is taken to represent the future of America, the stoned, incoherent, swaggering, loudmouthed teenage party fiend, concerned only for his own hedonistic fun. Played with great gusto and wit by the excellent ­ and formerly Perrier-winning ­ Will Adamsdale, it turns out to be exactly how America turned out.

Not that the barely-revelatory take on the state of the nation are what this play is entirely about. It's more of a comment on the messianic figure of Champlain, whose warnings fall on deaf ears and whose message of tolerance, humanity and thinking for yourself misinterpreted by his followers. Sorry, listeners.

Director Stewart Lee knows a thing or two about that, given his run-ins with the Christian right over Jerry Springer: The Opera, but Talk Radio is very much Nichol's chance to shine as the hard-drinking, chain-smoking (well almost, to circumvent the new smoking laws he doesn't actually manage to get any fags to light) hero.

That he does with a powerful, climactic speech to the audience, starting from a crisis of confidence and turning into a diatribe against all those who think all the answers lie in him, not in themselves. This is an impassioned, intense performance which brings the piece effectively to its ambiguous conclusion with a sense of purpose sometimes missing from the preceding scenes ­ and proves that Nichol was the best man for the job, even if he is the boss.

Steve Bennett