Andrew Lloyd Webber must be the cultural opposite to a writer of fantasy fiction. George R.R. Martin has been working on A Dance Of Dragons for over seven years and is probably going to snuff it soon. Andrew Lloyd Webber, by contrast, has musical diarrhoea.

Why ... in ... God's ... name ... won't ... he ... stop.

The man has a damn near infallible eye for things I really rather like and would prefer not to have turned into blisteringly mediocre musicals with one decent song that sounds exactly like every other decent song Andrew Lloyd Webber has ever written. Way back in 1975 when, thankfully, I wasn't around to see it he fastened his beadies on the work of PG Wodehouse and created Jeeves, which Wikipedia kindly calls "his only flop." Unable to leave well alone, Lloyd Webber and Alan Ayckbourn got together and re-wrote the thing pretty much from the ground up and the re-named By Jeeves opened to what I presume must have been acceptable success in 1996. Now a new UK Tour, produced by Eastbourne Theatres, is doing the rounds and I'm much a mellower person than I used to be. I've managed to develop a grudging affection for the mediocre bombast of The Phantom of the Opera, so I can just about cope with Andrew Lloyd Webber cocking his leg over one of my very favourite authors.

To be honest, I'm not too keen on Alan Ayckbourn either.

My fondness for PG Wodehouse being as pronounced as it is, I'm probably not an ideal audience for this show but, ultimately, it's an enjoyable piece of nonsense that fails to live up to its source material and, indeed, the rich heritage of previous adaptations, including Stephen Fry and Hugh Laurie's and the old BBC radio versions starring Richard Briers and Michael Hordon as the most perfect Jeeves and Wooster you could possibly imagine. Essentially it comes down to this: Wodehouse was a comic and literary genius, not a term I use lightly or ill-advisedly but he was. At best, Lloyd Webber and Ayckbourn are two guys who write stuff. It's less of an adaptation than an in-joke about how much we all love Wodehouse.

This sense of complicity is established straight away with the audience cast in the "role" of church-goers attending a fund-raising concert starring Bertie Wooster playing the banjo. It's a nice little device but it feels too self-conscious and the funniest thing about Harold Stinker' Pinker's seemingly interminable introduction is a bit of slapstick involving a music stand he breaks. The attention to detail is nice - I believe Bertie once comments that Stinker "couldn't cross the Gobi desert without knocking something over" - but it's a clumsy beginning. Bertie enters for his banjo solo but, shock, the banjo has been stolen and Jeeves suggests that, while they wait for a replacement to arrive from Kent, he could entertain the crowd with anecdotes instead.

This torturously contrived device then allows Bertie to both narrate and participate in the story he proceeds to tell the audience - a moderately flavourful piece of thwarted lovers and mistaken identities - in a style reminiscent of the original books. The various members of the church community then enter to "play" the parts within it and, throughout the story, the sets and props are deliberately presented as makeshift, with Bertie often commenting on their (in)appropriateness. The few Ayckbourn plays I have bothered to read have messed about a bit with audience awareness and the meta-textual dimensions to plays - in this instance it's not unamusing but it does get in the way and the musical loses energy as it reels beneath the weight of its own unnecessary theatrical devices.

This is saved from being basically-not-very-good by the sheer joyous energy of the cast, some inventive set pieces and the choreography. The songs are okay-ish, occasionally aspiring to quite decent - particularly Banjo Boy, Love's Maze, By Jeeves and What Do You Have To Say, Jeeves. At the other end of the spectrum, despite its pace, It's A Pig has to be one of the most pointless songs in the history of Andrew Lloyd Webber. But there's lots of slightly 1920s, Charleston inspired dancing which works wonderfully and pop-up Maypole and the related charge of Morris Dancers across the stage is hilariously English.

Robin Armstrong as Bertie Wooster is an absolute pleasure to watch. I've always thought Bertie might be my perfect man (rich, endlessly amiable and a little bit stupid) and now I'm sure of it. He bounces about the stage on elastic legs, exuding fluffy-headed bonhomie, waggling his eyebrows and occasionally bestowing worried, sickly smiles upon the audience as his situation grows ever-more tangled and banjo-less. And his impression of a dressage horse is worth the price of admission alone. Jeffrey Holland's unfalteringly dignified Jeeves is equally well done - his relationship with the audience is rather more comfortable, he spares us a wry glance and a half-smile every now and again, as if he is in on the joke. The rest of the cast all perform adequately although there isn't really space or scope for their roles to be any more than brief sketches. Madeline Basset is drippy, Honoria Glossip is tomboyish, and Stiffy Byng pouts and schemes. Their lovers are even less differentiated: Gussy Fink-Nottle is vaguely wetter than the others and Bingo Little is short but, for the most part, they're disappointingly interchangeable.

It's almost sad really because thing has obviously been done with extraordinary affection and that, at least, comes through. The stage management is imaginative and the songs and dialogue aspire to a Wodehouseian style even if they fail to even approach his wit. It doesn't quite work but the enthusiasm of the cast carry it along and it's reasonably good fun if you're in the mood to be generous.