Ayckbourn goes for the double

House/Garden | NT Olivier/Lyttelton, London

Talk about a takeover at the National. It's some time since Alan Ayckbourn has had an original work mounted at this address, but his return now is not so much a visit as a full-scale occupation. For the next few weeks, House and Garden, his ingenious comic double-act of dramas, will be monopolising not just the Olivier and Lyttelton stages, but also annexing the latter's foyer for the spoof summer fête that ends the afternoon-and-evening marathon. This is a quest for Lebensraum with a vengeance. If I were Trevor Nunn, I'd be double-locking my office.

Talk about a takeover at the National. It's some time since Alan Ayckbourn has had an original work mounted at this address, but his return now is not so much a visit as a full-scale occupation. For the next few weeks, House and Garden, his ingenious comic double-act of dramas, will be monopolising not just the Olivier and Lyttelton stages, but also annexing the latter's foyer for the spoof summer fête that ends the afternoon-and-evening marathon. This is a quest for Lebensraum with a vengeance. If I were Trevor Nunn, I'd be double-locking my office.

In Noises Off (soon to be revived at the National), Michael Frayn famously revolves the action so that you are alternately privy to the onstage and the backstage antics of a frightful rep farce. House and Garden play a witty variation on this conceit, that every exit in life is an entrance somewhere else. Here, Ayckbourn has the same set of actors racing between two separate but interlocking dramas which cover simultaneous events and are also, by a devilish twist, performed simultaneously in two different theatres and before two distinct audiences.

This diptych was unveiled last summer in Ayckbourn's Scarborough home base, where the dash from one auditorium to another is a relatively easy sprint. There is, however, an added piquancy in the author's expertly drilled and semi-recast production for the National because the greater distance between the theatres creates a logistical backstage nightmare of colour-coded staircases, frazzled stage managers and breathless, colliding thesps. It can't be long before someone writes a farce about just such a perilous behind-the-scenes predicament.

Reflecting on the overall wizardry of the proceedings is quite a bit more fun, I feel bound to say, than the experience of watching the plays in sequence. Clockwork technique and Cluedo characterisation predominate, by and large, over genuine comic depth. The pieces are set, respectively, in the sitting-room and the stately grounds of Teddy Platt, an adulterous country grandee (played by the excellently hapless David Haig) who is being sounded out by an enigmatic political fixer and old school friend (Malcolm Sinclair at his most comically cold-blooded and lizard-like) about standing as the local MP.

Teddy's political prospects aren't exactly enhanced, however, by the fact that his betrayed wife (starchy Jane Asher) is now making a public display of refusing to acknowledge his existence, or that, out in the garden, his mistress (crazed Sian Thomas) is undergoing her own marital crisis with Michael Silberry's mild, culpably innocent morris-dancing buff, Giles. To put the tin chapeau on it, there's the disruptive arrival of an unstable, sexy French film star (Zabou Breitman) who ends up opening a good deal more than the rain-bedevilled fête.

Performing in front of two audiences at the one event must feel like committing bigamy or adultery, but House and Garden don't make nearly enough of the way the two-timing of the characters is mirrored in the form. Despite the publicity, neither play is really free-standing. Indeed, Garden is so much the weaker work that watching it is like listening to a piano recital where only the left hand is being used.

In both plays, though, there are undeniably entertaining patches and time-honoured Ayckbournian preoccupations, as three marriages founder through the blithe male insensitivity of nice as well as nasty characters. You don't need to be the fortune-teller at the fête to predict that the National is sitting on a safe middlebrow summer hit.

In repertory, 020-7452 3000. A version of this review appeared in later editions of yesterday's paper