Aileen, a substantial young woman who would surely, in her native Glasgow, be called a barger, is controlling the remote control. The other inmates of this mental hospital – immediately recognisable by the mismatched chairs and door security system – squabble about what to watch. Into this torpid environment creeps Eddie, a soul DJ-turned-window-salesman in a tweed jacket. His shoulders are down, his box of Sam and Dave singles battered, a quarter bottle stashed in his pocket. When he meets Campbell, a Tigger-manic teenager with chutzpah and patter in equal measures, no one is going to be catching Emmerdale in the foreseeable.

Three quarters of Donna Franceschild’s 1994 TV series telescopes brilliantly into this funny, moving, relevant piece of theatre. Brian Vernel, still a student at the Royal Conservatoire of Scotland, is astoundingly good as the dangerously effervescent kid who calls his radio debut Campbell Bain’s Loony Tunes Show. Iain Robertson is an effectively tortured Eddie, self-deprecating, humane, living on whisky and a hefty overdraft. Together with Rosalie, a germ-phobic, cross-referencing, spreadsheet producing Caroline Paterson, they get the inmates out of their seats and into their dancing shoes.

This is all grand and these characters have time to drop their backstories into the black humour and Mavin Gaye tunes. What gets lost, however, is Eddie’s relationship with Francine, a damaged young woman who has illegally adopted a stray cat. Unlike his chemistry with Campbell, which has time to unfold organically, this feels shoehorned in. And Helen Mallon, playing weepy, broken Francine, is easily lost in this outstanding ensemble cast: the ebullient Vernel, Martin McCormick as a casually brutal orderly nurse, Grant O’Rourke as inventive escapologist Fergus and Gayle Madine’s frankly terrifying Aileen.

This may be less of an issue to those who don’t remember the TV version – which had the luxury of six episodes – so fondly. It’s certainly not a reason not to see this fantastic piece of old-school theatre.

Citizens Theatre, Glasgow, until Sat 9 Mar; Royal Lyceum, Edinburgh, Wed 13 Mar–Sat 6 Apr.