It’s doo-be-doo-be-Doomsday in this cheerful, well-mannered, furrow-browed 80-minute a capello quest to save the world from the Three Horsemen of the Apocalypse.

A primary school play in the St Ann’s Leisure Centre is commandeered as the focal point: now dubbed Satan’s Leisure Centre, eager teacher Beth is recruited as the Fourth Horseman, Death.

But God is always in the room, eventually materialising as a small pink cow in the manger of the school’s nativity play, where the little puppet Jesus wields a magic pen, and the Horsemen depart in search of the lost three commandments.

They visit an orphanage run by a suspiciously hairy nun, Sister Tufty; they climb aboard the Jolly Roger with Peter Ham (as in the old days, the boy’s a girl) and Captain Melonscoop (nicer than a Hook); and they overcome the hound of hell and spring-clean his dirty den.

Barbershopera have been a hit on the Edinburgh Festival fringe, their spiritual home, and there’s no questioning their ingenuity or musical ability, though the songs start to wear a bit thin after half an hour or so.

This is very much the world of the Radio Four comedy pilot: it’s the Goons without delirium or genius, the whole caper wrapped up in an audition for archangels on the eve of the biennial assault on the human race.

Hats off, though, to Rob Castell, Tom Sadler, Pete Sorel-Cameron and Lara Stubbs: all likeable, all talented, and one of them, a simian sourpuss with a stubbly beard (not Lara) has a voice that can gurgle nastily like ditchwater down a drain.

Not only is the world saved: also, Beth’s job, as well as the Horsemen’s inner nice guys, and the future of primary school nativity plays in this country. Hooray!

- Michael Coveney

Please note: The following FOUR-STAR review is from the production's run at the Pleasance during the 2010 Edinburgh Fringe.

Creating a Fringe hit is difficult, repeating it is even harder, so pity the cast of Barbershopera who in 2010 are tasked with ensuring their unique brand of acapella musical comedy garners the critical acclaim a third time round. Apocalypse No! is the title of this year's adventure: the four horsemen are sent on a mission to destroy the planet but mistaken identity leads to a primary school teacher joining their ranks.

Fun and frolics in faultless four-part harmony is frankly irresistible. This choral quartet of three guys and one girl are experts in masking their precision and professionalism with silliness and faux incompetence. And unusually for late-evening entertainment, this has universal appeal and won't scar the kids with smut.

But why does it begin at 10.55pm when youngsters and pensioners in the audience have to stifle yawns in between bouts of laughter? Thankfully there are family-friendly matinées on 16 and 23 August. Barbershopera is swiftly turning into a festival institution, you'd be irresponsible to miss out.

- Joeseph Pike