The Witches, Wyndhams Theatre, London

One wonders what the Conservative MP Peter Luff would make of Roald Dahl's The Witches. Mr Luff made the headlines recently with his criticisms of Dick and Dom in da Bungalow, the BBC Saturday-morning show that is increasingly making that bygone byword for unwholesome entertainment for little people, Tiswas, look as tame as Listen with Mother.

One wonders what the Conservative MP Peter Luff would make of Roald Dahl's The Witches. Mr Luff made the headlines recently with his criticisms of Dick and Dom in da Bungalow, the BBC Saturday-morning show that is increasingly making that bygone byword for unwholesome entertainment for little people, Tiswas, look as tame as Listen with Mother.

Dahl's tale, in Jonathan Church's production (adapted by David Wood), calls Dick and Dom to mind, peppered as it is with bodily-function-based humour, nose-picking, green vomit, blue spit and even a little custard-pie-and-mashed-potato-throwing. The children in the audience (and the grown-ups, under cover of theatrical darkness) shrieked gleefully.

The Witches, however, is no mere festival of fart gags and flan-flinging. "This is not a fairy tale," Dahl states at the beginning of his book. "This is about real witches." Of course, the witches aren't real, but it is the realism in which the fantastical tale (of witches wishing to turn the entire child population of England into mice) is couched that is key. As so often in Dahl, there is darkness at the heart of the narrative - here, Boy (Giles Cooper) loses both parents in a car accident. The easy daftness of Terry Pratchett this is not.

Boy goes to stay with his pipe-smoking, Norwegian grandmother (Dilys Laye), something of an expert on witches, and his adventure unfolds in a production packed with rough theatrical magic. There have been more sophisticated spectacles of late - the ingenious staging of the National's His Dark Materials and William Dudley's computer-generated back-projections in, among others, The Woman in White are called to mind here.

But the very simplicity of the piece, with its blend of puppetry and slapstick comedy, beguiled even young audience-members - no strangers to being spoon-fed special effects. During a great Laurel-and-Hardy-style mute sequence, in which two mice - Cooper and Keith Saha in skins - attempt to scale a mountainous staircase, you could have heard a pin drop between the outbursts of laughter. And this even though there were very young children in the auditorium.

The biggest star among the cast is very much the least effective element of The Witches. Ruby Wax as the Grand High Witch, with a generic Eastern-European-baddie accent ("veetch" for "witch", "cheeldren" etc) that makes her come over like the Cheeky Girls' big sister, seems somehow smaller as a Grand Guignol villain than she does in her own persona. Often, if it hadn't been for the Edward Scissorhands-ish scary music (courtesy of Matthew Scott), we might have forgotten to be scared.

But Wax cannot unbalance a great ensemble piece or break the theatrical spell. As the gluttonous Bruno (a wonderful Saha) was turned into a mouse, in a scene with all the pomp and chutzpah of a magic show, a little girl nearby gasped: "Is it a real mouse?" Indications of disbelief-suspension don't come any clearer.

To 2 April (0870 060 6633)