Question: how do you make a send-up of a soap opera more fantastic and improbable than the real thing? After all, the convoluted plotlines of EastEnders, Neighbours et al are hard to beat. But with Soap, playwright Sarah Woods has a determined crack at the challenge.

Things begin conventionally enough. The curtain rises on a seedy pub in Arthur Street, London E1, whose over-gassed beer is drunk only by the landlady's warring relations. Soon, however, said landlady's right to hold the licence is challenged by one Annabel, who - surprise, surprise - is a dead ringer for the late lamented Angie Watts from EastEnders. How does Annabel remove her predecessor behind the bar? She locks her in the cellar.

But the cellar door doesn't lead downstairs to barrels of badly kept beer. Courtesy of Philip Witcomb's brilliant, revolving, set design, it leads straight on to the deck of the Jack Rabbit, a vessel basking in the Australian sunshine. Cue entrance of girls called Noleen and Lisa, plus two hunky surfers. "The only thing I know about myself is my name, and I've never told anyone that much about myself before," confesses Lisa as she cosies up to one of the hunks. Gradually the two spoof soaps, the London Arthur Street and the Australian Crystal Bay, merge into one hilarious confection, complete with fights, an aborted wedding, and, of course, a hospital scene, where one of the hunks ends up connected to a frantically bleeping monitor.

The ensemble cast members (Lucy Speed, Marc Bannerman, Mike Burnside, Louise Callaghan, Stephen Critchlow, Janice McKenzie, Natalie Walter, Sharon Corrodus, and Paul Ennerver) have a goodly amount of real-life soap experience between them. They double across both spoof soaps, involving constant, hair-raising costume changes as the action switches backwards and forwards between London and Australia. Directed with a sure hand by Laurie Sansom, they dexterously handle Sarah Woods's appropriately machine-turned soapland dialogue without overacting in the process. Cerebral theatre this ain't, but a piece of fun it certainly is.

The comedy continues at the Royal & Derngate, Northampton, until Saturday, March 24.

Tickets: 01604 624811