Michael Coveney (What's On Stage)The show's a delight, a clever synthesis of several stories involving a kind-hearted elephant Dr Seuss's "Cat in the hat" stories are a staple diet of kindergarten culture on the other side of the Atlantic and deserve to be much better known here than they already are. They are smart, wise and funny, and they formed the basis of a seriously underrated 12-year-old Broadway musical (all the best ones are) by the Ragtime and Once On This Island team of composer Stephen Flaherty and lyricist Lynn Ahrens; their show was co-conceived by Eric Idle. So here comes what they call "the theatre for young audiences version" in matinée performances for the Christmas season while Simon Callow holds down the evening slot with a re-run of his not-to-be-missed A Christmas Carol. There's one big problem: the sound. The music is a pre-recorded soundtrack (loathsome, atmosphere-killing, cheapskate habit; can we stipulate live musos at all Christmas shows from now on, please?) and the microphoning's abysmal. There's a tinny, eardrum-assaulting quality to the words and music that needs sorting out urgently. Otherwise, the show's a delight, a clever synthesis of several stories involving a kind-hearted elephant (beautifully done by David Hunter), a threatened humanity of dust specks on his jungle clover and some jungle bad boys. The score is a charming, witty and wholly melodic parade of pop and soul idioms, with slinky jungle maidens, some mean, leather-jerkined monkeys and a couple of devious divas – Natalie Green's sumptuously sonorous sour kangaroo and Jessica Parker's slutty Mayzie La Bird. Horton the elephant's admirer Gertrude McFuzz (Kirsty Marie Ayers) grows a bushy tail to impress him but wins in the end after surgery, a moral to enforce the heart-warming Dickensian sentiment that “a person’s a person no matter how small,” something Horton sings to us early on. This is to do with the dust showing up on his clover, and his instant friendship with Clark Devlin’s eager-to-please specimen speckle, unhappy son of the Mayor of Who’sville (with a sign post to the Whoses of Parliament).