THEATRE / Golly gee and aw nuts: Paul Taylor on Lady Be Good in Regent's Park

Lady Be Good, the first musical on which George and Ira Gershwin collaborated, was expressly written to showcase the singing and dancing talents of that celebrated brother-and-sister team, Fred and Adele Astaire - the William and Dorothy Wordsworth of fancy footwork. Consequently, Guy Bolton and Fred Thompson's book centres on a pair of siblings; but don't go thinking that it heads anywhere near 'Tis Pity She's a Hoofer territory. This is Broadway 1924, remember, when innocent young heroes still say things like 'Oh, I'm so gosh-darn blue,' and a kiss is just a kiss (if you're lucky). It's a pre-Depression world; so when people are thrown on to the streets through poverty (as happens to our siblings), they think it's the darndest scream and set up house on the sidewalk, merrily plugging the electric kettle into the street lamp with the aid of a passing policeman, and then Charlestoning under the rain.

Porgy and Bess it isn't, but only a career misery could remain completely resistant to its inane charm. For the first half-hour or so of Ian Talbot's amiable revival at the Open Air Theatre, Regent's Park, this reviewer managed to remain pretty impervious. Everyone makes such a strenuous effort to give the proceedings a bright, giddy, party-like atmosphere that you feel like pleading a headache and retiring. And it's not until the lovely sixth song, 'So Am I' (a duet beautifully sung by Zubin Varla and Joanna Riding), that you sense the first real tremor of romance and sexual attraction. Call me insatiable, but that's too long to wait.

Things warm up with the arrival of Bernard Cribbins's engagingly (and incompetently) shady lawyer Watty Watkins. To help himself and the impoverished heroine make some dough, he persuades her to impersonate the Mexican widow of the man she has fallen in love with. He's not dead; the widow was never alive - yes, it's the kind of plot that contrives to be both brainless and so involved you need to be a near-genius to keep track of it. Suffice it to say, this is not a show to take Mexican friends to (at least, not if you want to keep them). And its moral seems to be there is no unhappiness that inheriting a fortune can't comfortably cure.

Gavin Muir is perfection as the period silly-ass Bertie Bassett who, on his wedding day, manages to handcuff himself to the lawyer and lose the key. The sight of him and his squeaky sweetheart Daisy (Samantha Spiro) gurgling at each other like demented percolators while Cribbins, a literally captive audience to this fatuous foreplay, tries to get on with a crossword is the sort of daft pleasure the show abundantly affords.

On the debit side, Talbot's production is unevenly cast and, despite including a couple of standards (like 'Fascinating Rhythm' and the title song), this is far from being the finest of the Gershwin Brothers' collaborations. But whether as clowning cook or as love-interest, Riding's Susie, the sister 'who's / Got Her Brains in her Dancing Shoes', lights up the stage. 'Swonderful, 'smarvellous - 'spatchy.

'Lady Be Good' is in rep at the Open Air Theatre until 10 September (box office: 071-486 2431); then tours to Dartford, Darlington, Oxford, Coventry, Cambridge, Lincoln, Brighton and Blackpool (details: 071-935 5756).