We might be living through a credit crunch and rampant food-price inflation but if Lucy Kirkwood’s predictions are correct, we’ll soon be looking back on these as halcyon days. In Tinderbox, her first full-length play, this young writer peers into the near future and foresees a desolate, dystopian country where environmental chaos rules, the yen is the currency du jour and there are riots on the streets.

With all these promising elements in place, it is baffling that Kirkwood then proceeds to focus almost exclusively on the smaller picture. She rustles up too little plot momentum for the ever-decreasing-circle events inside a butcher’s shop, where psychotically patriotic Saul (Jamie Foreman) and young wife Vanessa (Sheridan Smith) have their peculiar rituals interrupted by the sudden arrival of affable Scottish fugitive Perchik (Bryan Dick).

Snappy direction from Josie Rourke can’t quite disguise the fact that the tone of the piece becomes increasingly uncertain. The farcical elements — comedy policemen called Dixon and Dock; references to Vanessa’s starring role in Fellatio Nelson, a party political porn film for the Conservatives — aren’t pushed far enough, despite valiant performances from Dick and, especially, Smith. Her quick-talking presence, complete with saucy twinkle in eye, is a constant, energising delight.

Designer Lucy Osborne has transformed the Bush’s two-sided playing area into an end-on proscenium-arch stage, an intriguing experiment that is well suited to the various contraptions of Saul’s shop but less kind on audience bottoms.

Tinderbox until 24 May (020 7610 4224, www.bushtheatre.co. uk)