This fabulous drama, wonderfully portrayed by Claire Sweeney, is a must-see. Even with a premature call of ‘Cut!’ says Katie Jarvis

Shirley Valentine is speaking to the audience from the depths of her kitchen, where she's chopping potatoes, ready to put an egg-and-chips supper in front of Joe, her husband. (It would have been mince, had she not taken pity on a vegetarian bloodhound.) Although we've only just met Shirley, we already know that Joe isn't an egg and chips sort of man.

Oh-uh.

The audience - at a rough estimate, 90 percent women-and-counting - is on intimate terms with Shirley, despite such a recent acquaintance. The woman a few seats down from me is actually replying to her, with a lack of self-consciousness that indicates she'd be astonished if you pointed it out. "Oh no!" she says, at one point. "That's right," she agrees, at another.

When Shirley, mid-chip, announces, "I've just cut my hand on the knife," everyone nods. We've all done it while making inadequate egg-and-chip suppers for our demanding husbands.

"No," says Shirley. "I've cut my hand on the knife."

We laugh - one of many bonding laughs.

"No," says Shirley, trying to make us aware that she's now Claire Sweeney. "It's quite bad."

We all screw up our eyes and stare from the back of the stalls/circle, while someone in the front of the stalls gets up and puts a packet of plasters on stage.

Shirley Valentine - though much more Claire Sweeney - is dripping blood in a non-stagey way.

"I once saw a play where the actress, who was wearing a white dress, suffered a severe nose bleed. She carried on," says the person next to me.

"I'm going to have to get this seen to," says definitely Claire Sweeney.

Now I'm not trying to do a Scottish Play-Type-Thing. But, interesting, when Shirley Valentine opened in 1986, the actress - Noreen Kershaw - had to drop out with the sort of burst appendix that no one in the stalls would have tried independently to fix. With no understudy, in sight, there was one option: the man who wrote the play - the fantabulous Willie Russell - went on stage for the last three weeks to read the part from the script each night. The theatre was packed. And the Liverpool Daily Post, while awarding Best Actress to Noreen, endowed Willie with Best Supporting Actress.

If I might introduce a corporate analogy for one moment here: once, Ian was at a work seminar, when the lecturer walked in and dropped to the floor. Everybody waited politely for the reveal; until someone realised he'd just had a heart attack. That's a facet of the days when people tried to make workshops fatally inventive.

Tonight's semi-debacle is a credit to writer Willie Russell, director Ian Talbot, and so, so much to Claire Sweeney. What an absolute trooper. Not only did she leave the stage while vital repairs were carried out; she then came back on and - with barely a misstep - continued her whole performance. And this play asks for some performance. A long monologue, in a Liverpool accent, that needs pinpoint timing; perfect comic intonation; and the sort of rapport with the audience that means you could accidentally sever your hand and no-one would notice.

And wow, this is a fab play. You can read all about how Russell left school at 15 and started life as a hairdresser; you can intuit from that how he got an ear for women's chat; for their lives, their humour and their grievances. You can double that when you realise that the women he grew up around were Liverpudlians.

But you can't square the circle without throwing in Russell's sheer genius. His understanding of character; his sympathy with women who are trapped in a life far smaller than the one they envisaged.

"Clit-oarrr-is," intones Shirley, who was 28 before she even heard the word.

She thought it sounded like a good name.

"Why not. There's plenty of men walking round called Dick."

And balanced against the laughs is the sadness. "I always said I would leave him when the kids were grown up. But once they had grown up, there was nowhere to go."

If Claire Sweeney was busy dealing with untoward emergency in the first half, she did a solid job. But she came into her own in the second. As the Greek sunlight poured onto the stage, so she flowered.

And gave a taste of the run to come.

Go and see Shirley. You might not have quite the drama we did; but, honestly: there's drama enough in the brilliant script.

The Everyman Theatre is at Regent Street, Cheltenham, Gloucestershire GL50 1HQ, box office 01242 572573; www.everymantheatre.org.uk

Willy Russell's hit comedy Shirley Valentine, directed by Ian Talbot and starring Claire Sweeney, is at Cheltenham Everyman, February 13-22