Theatre review: If Only, Minerva, Chichester Festival Theatre

The best play to date about the tragicomic compromises and ignominious ironies of coalition politics is Michael Frayn's Democracy (2003) about the unstable, ill-natured, ideologically bizarre groupings on which power depended in post-war Germany.

When it was revived last year, the piece spoke with sharp pertinence to our current predicament but it also has a metaphoric reach (democracy seen as the political system that answers best to the contradictory self-divisions within individual voters) that will give it real staying power in the repertory.

David Edgar, by contrast, is quite prepared to admit that If Only – his witty, somewhat exhaustingly clever new play which tackles the dilemmas of the Cameron/Clegg coalition head-on – probably has a short shelf life. This is not least because its second half, located in August 2014 against the backdrop of First World War centenary commemorations, is in the predictions game.

It posits a scenario where the dystopian shadow of UKIP is darker, and Cameron, in an effort to ward off a leadership challenge, is planning to chase their vote by withdrawing from Human Rights agreements and announcing repressive policies on immigration, law and order and welfare.

Edgar's main contention, powerfully articulated, is that this state of affairs is a disturbing unintended consequence of the coalition project itself. Instead of neutering their extreme wings, the parties have effectively allied the middle with the rich against the poor. Premiered in a spry, spiritedly acted production by Angus Jackson, the play, though, too often comes across as a Yes, Minister for policy unit boffins and wannabe wonks.

Stranded on the continent by the volcanic ash cloud in April 2010, three youngish apparatchiks – a Labour Special Adviser (Martin Hutson), a Liberal Democrat staffer (Charlotte Lucas) and a Tory MP (Jamie Glover) who's been fingered for his pergola in the expenses scandal – are drolly flung together in a clapped-out Peugeot in their struggle to get back to the election campaign.

As they 'war-game' the permutations of a potentially hung parliament, there are plenty of good gags (I like the idea that it would be better to claim “a particularly lengthy sojourn in the Priory” than confess to having worked for Gordon Brown between 2007 and 2010). But the play keeps losing sight of the wood for the trees, becoming as nerdily obsessed by the amoral convolutions of strategy as the wonks are.

Likewise, a complicated pact involving the threat of mutual exposure gives too little breathing space to the emotional side of what should be their moving climactic and chastened transition back from political operators to principled human beings.

To 27 July; 01243 781312