THEATRE: The Landslide West Yorkshire Playhouse, Leeds

Strange how a new play that is not only up to the minute but plausibly beyond it should be so old-fashioned. True our first sight is of the lady of the house carrying a cafetiere rather than a maid carrying a silver tea-pot, but in every other way we could be in one of Pinero's social plays. Bang Andy de la Tour's walls and they sound reassuringly of the joists of solid construction and best lime-and-hair characterisation. This is appropriate enough, for the work depends on the kind of exact social detail - well delivered in Gwenda Hughes's production - that only realism can provide. It becomes apparent, too, that its stylistic devotion to tradition mirrors an ideological one.

The landslide of the title belongs first to Tony Blair and to the new MP for Benton, Felicity - or more New Labourishly, Fliss - Anderson (Jenna Russell). It took a 19 per cent swing to dislodge St John Hewitt from the seat his forebears had held since Lloyd George was in his pomp, but St John, a quintessential One Nation man with a mind as broad as his acres, is apparently taking it well. When Fliss comes to Benton Hall to enlist his aid in shelving an intrusive local development plan he acquiesces. "How very civil this country is," says his son Peter. A little too predictably, the middle ground soon extends to the bedroom.

The attraction of Christopher Ravenscroft's St John is his patrician mix of languid grace and mocking acerbity, not least towards his own side. But, as a politician, he would not set Machiavel to school, he could teach him at home, and once having out-manoeuvred Fliss in furtherance of his own rapacious land-deal, he amuses himself by tutoring her.

She proves an apt pupil, and, ourselves undergoing a crash course in planning politics, we witness the skill and ruthlessness with which Fliss exacts her revenge and hauls herself the first few feet up Westminster's greasy pole.

The baleful and believable point is that the cynicism of decayed Toryism and the ambition of ingenue Labour meet on the same ground of self-seeking. As John Branwell's wonderfully gruff and wounded Old Labourite, and Deborah Norton's Tory wife, both recognise, neither St John nor Fliss have any value system outside their own interest. De la Tour's satire of both is well observed and, until the melodramatic conclusion, fillets very finely.

But, like most satirists, his vision is fundamentally pessimistic and nostalgic. His disgust at St John is mainly at the personal pathology, glimpsed from the start in Ravenscroft's lip and eye, which is destroying Peter (the fine Raymond Coulthard). The only cynosure is the wife, Jessica, with her dignity, good works and profound sense of the family's duty to its inheritance and the community. Nuanced and sympathetic as Deborah Norton is in the role, if New Labour can furnish no more than Lady Bountiful's trug we are in trouble.

To 5 April. Booking: 0113 244 2111; then at Birmingham Repertory Theatre, booking: 0121 6446464