The Umbrellas of Cherbourg, Gielgud Theatre, London

Camp? Well, let's put it this way. Kneehigh's stage adaptation of Jacques Demy's Gallic, unashamedly romantic and singularly through-sung 1964 movie musical was only half way through its cod introduction when I was assailed by a sudden Proustian memory. It was of an edition of Just a Minute in which Kenneth Williams was given, as his subject, the phrase "Honi soit qui mal y pense". "Translated into yer actual English," the great man averred, "that means 'Honest sweat killed many a ponce'."

"Manhandled by Matelots" could be the subtitle of this theatrical adaptation, which boasts a trio of butch dancing sailors who seem to have swaggered in from Genet's Querelle de Brest and who keep lifting the characters into supposedly revealing stage pictures. The director/adapter Emma Rice has also equipped the material with an archly demimondaine narrator-figure, "Maitresse" in the shape of the great comic cabaret diva, Meow Meow.

The irony is that this hilarious artiste is both the best thing about the show and an unwitting act of sabotage given that her rapport with the audience and her scandalous/mock-scandalised antics serve to expose the enervating wispiness of the central story. At the start, Maitresse clambers over the front rows, her legs thrust out in ballet extensions designed to offer the punters a gynaecologist's-eye-view of her assets. She then gives us crash course on Cherbourg and on its strange customs – the locals never stop singing.

She can say that encore une fois. The most salient feature of the screen musical is that, though it has only one real song, the plangent reprised-to-death "If It Takes Forever (I will wait for you)", all the dialogue, including the most thudding banalities, is sung too. I'm normally a huge admirer of composer, Michel Legrand. But much of the brush-on-cymbals-hustled jazz music here sounds like so much doodling and the English translation is often risibly flat. So I'm afraid to say that this account of The Umbrellas of Cherbourg kept reminding me of the game on I'm Sorry I Haven't a Clue where they struggle to fit the words of one song on to the tune of another.

Boy meets girl. He's a garage mechanic and she loves the smell of petrol. Boy gets called up for military service in Algeria. Pregnant girl marries rich admirer to save her mother's umbrella shop. Boy returns, goes through period of drunken dismay, and survives thanks to the loving support of another woman. Joanna Riding is a class act as the financially and emotionally strained soigné mother, but Carly Bawden lacks the vulnerability necessary for the heroine and neither she, nor the touching Andrew Durand, have any of the sex-appeal of Catherine Deneuve and Nino Catelnuovo in the movie.

Kneehigh's approach to love stories in the past has been to take classic romances and either to demonstrate how they can survive a spirited debunking (as in their very amusing Tristan & Yseult) or exuberantly to release the subtext (as in their wittily passionate crinkling of the stiff upper lip in their stage version of Brief Encounter). Here, though, they impose similar techniques on a fragile story that can't survive them. Ce n'est pas magnifique et ce n'est pas la guerre. Et surtout, pourquoi?

To 1 October (020 7907 7071)