Irina Brown's production of The Importance of Being earnest points up the play's modern interest in social shifts and transformations but presenting it in the open air means that some scenes lose the close-quartered intimacy they need.

The set poses real problems. Algernon's London flat, furnished here in Ikea white, resembles a municipal leisure centre. A mirrored bank, intended to suggest the characters' narcissism and plural identities, dazzles uncomfortably.

For the pastoral second half, the stage is dotted with individually planted roses. The actors have difficulty weaving between these and when for the final act most of the roses have to be removed the cull is laborious - an interlude symptomatic of the production's rather ponderous pacing.

There are some nice stylised touches (such as Cecily's elaborately negligent preparation of Gwendolen's tea) but also some questionable ones, as when Cecily is immured in an oversize doll's house - a clumsy comment on patriarchal oppression.

Jo Herbert's Gwendolen is poised and Lucy Briggs-Owen's Cecily suitably pert, while, in the key role of Algernon, Dominic Tighe proves at once languid and fluent. Less satisfactory are Ryan Kiggell's bumbling Jack and Susan Wooldridge's Lady Bracknell. The latter, initially sporting an enormous hayrick of a hat, is a puzzling combination of gorgon, jaunty pragmatist and faded coquette, and in her more indignant moments hoots unnervingly.

Although Wilde's comic brio ensures that there is plenty to savour, this production lacks charisma and some of the necessary zip.

Earnest until 25 July (0844 826 4242).