THEATRE / Miracles for the suckers: Paul Taylor watches Paul Nicholas as Barnum at the Dominion

Paul Nicholas's voice sounds quite extraordinary in Barnum - so over-amplified you keep expecting it to announce disruptions on the Perth to Penzance line, with BR's apologies for the inconvenience caused. After a while, however, the ear starts to adjust. Whereas I could only distinguish about one word in eight in 'The Museum Song', a fast catalogue-ditty in Act 1, my score was roughly twice that for the penultimate number, 'The Prince of Humbug', with its high-speed synonyms for trumpery. Given the general lacklustre state of Michael Stewart's lyrics, it's hard to say whether your pleasure is doubled or halved in the process.

As glittering and synthetic as a fake tinsel tree, Cy Coleman's brash musical about the maverick American showman is fast becoming a regular feature of the festive period in London, this being its second yuletide revival in three years. It should, in theory, make a good Christmas show, combining the sentiment, song and dance of a musical with the thrills and stunts of a circus. In practice, it satisfies on neither count.

Presented now in a skilled, energetic production as the Dominion, the show makes extensive use of its star's familiar I'm-a-naughty-boy-but-God-am-I-winning grin, and Nicholas coasts through the proceedings on a great tide of audience good will (plus a certain amount of genuine charm). But the show gives him nothing interesting to work with and fails to offer a genuinely intriguing perspective on the character and his contradictions. Mark Bramble's meagre book has a narrative apparently modelled on the antics of a jumping bean. One moment, Barnum is becoming involved in an adulterous affair with the Swedish Nightingale, Jenny Lind (all tortured Scandinavian vowels in Clara Miller's vivid performance); the next, he's reconciled to his long-suffering wife (Carol Duffy). One moment, he's entering City Hall as Mayor; blink, and he's being dropped as his party's nominee for the Senate.

Apart from one promising sequence concerned with Barnum's ill-fated high- rise housing project (where the song and the staging have some proto-satiric edge), the show is disinclined to get down and explore the incongruities between its hero's idealism (wanting to give everyone 'a glimpse of the miracle') and his cynicism ('There is a sucker born ev'ry minute'). Instead, it keeps returning us with tedious frequency to the marshmallowy bogland of his marriage to the sedate, educated and miraculously forbearing Charity. Swirling in bold colours through it all, Coleman's music is what is sometimes called 'infectious'; who knows, next Christmas I may even be in a position to come out humming the tunes.

The Dominion Theatre, Tottenham Court Road, London W1 (071-580 8845).