Stop Messing About, Leicester Square Theatre, London

Infamy, infamy... they've all got it in for me!" It's typical of this so-called "Kenneth Williams Extravaganza" – based on the scripts of his 1970 radio show, Stop Messing About – that the funniest line actually comes from a Carry On movie. And it's not funny the second time, either.

As in an earlier retread of Round the Horne with the same team – actor Robin Sebastian as the outrageous Williams, director Michael Kingsbury and Brian Cooke, who wrote the original shows with Johnnie Mortimer – the aim is to create the exact atmosphere of the old radio comedy programmes in the recording studio.

So, the sketches are followed by an illuminated request for "applause" and the proceedings are (loosely) supervised by a respectable announcer in evening dress with a clipboard. Instead of Kenneth Horne, we have Charles Armstrong as the unflappable Douglas Smith who says things like, "That's a difficult song to forget... but well worth the effort."

The eponymous radio show was Williams's first starring vehicle after years of supporting others. But aside from those tumultuous virtuoso turns when he fronted a television cabaret programme and became the only act worth watching, Williams really specialised in needling from the sidelines.

Cooke's tour of his old material dredges up some classic movie spoofs – a send-up of Gone with the Wind with Yorkshire overtones, and a Mexican linguine Western, "The Dirty Half Dozen" in which Pancho Villa has a brother called Aston that are not really dependent on Williams shining.

Still, Sebastian pouts perfectly and shimmies round a stage defined by a row of functional chairs and four microphones. These shows were characterised by their live music, too, but here the sound-effects man in a brown coat does the whole job, and that's a loss.

Williams's sidekicks on Stop Messing were the priceless pair of Hugh Paddick and Joan Sims and it would be kindest to say that Nigel Harrison and Emma Atkins won't upset anyone who's never heard or seen the originals. The same gripe applies to the vocalisation of "E W Swansong's" cricket report from a reservoir, where drought has stopped play. Surely Cooke could have insisted on a fruitier reproduction of Jim Swanton's dulcet moans.

While Williams jeers lewdly at any mention of a knob or a joystick, Paddick has the best stuff: Sir Inigo Parchmutter is a "hanging judge" for reasons we won't go into who first took silk in 1937 but was never found out; and an item about aeroplane pioneers features an epicene plane spotter, tired of Alcock and Brown, hanging round the hangar waiting for Mr Wright.

The account of the London-to-Brighton Ballroom Dancing Rally remains a classic, butfor much of the evening you feel that, for the full impact, you really had to be there, and square, at the time.

To 24 May (0844 847 2475)