Coalition, Pleasance Dome, Edinburgh

Every politician needs a soundbite. For Matt Cooper MP, it’s “This party will not be broken on my watch”. Unfortunately for him, the party in question is the Liberal Democrats and it's breaking up faster than a matchstick raft on a waterfall.

Cooper, played with verve and shades of Blackadder by Thom Tuck, is the hapless anti-hero of Coalition, a hot-off-the-press satire written by someone who knows a bit about the impotence of being in power. Robert Khan has worked for the Labour party for a decade and is currently a Councillor for Islington in North London.

Together with co-creator Tom Salinsky he has put together a winning slate of comedian-performers: alongside Tuck, nominee for Best Newcomer at the 2011 Edinburgh Comedy Awards, Phill Jupitus stars as a silver-tongued Tory Minister without Portfolio (but with something of the night about him in a rather too campy turn), Jo Caulfield is a slinky, cynical Chief Whip and News Quiz staple Simon Evans puts in a cameo as the "marmelade-y voiced" PM.

The action unfolds four years into the current government, or “coalition of losers” as it's billed here. Cooper, a DPM who hasn’t spoken to his PM for six months is struggling with image problems (the opinion polls have him pegged as a "yellow amoeba"), the economy is in freefall and his party is on the verge of meltdown - literally, as he’s about to renege on his anti-Nuclear stance to unveil 12 new reactors.

The writers clearly know and love to hate their subject - the dirty deals in corridors, the niggly differences between 'strategy' and 'tactics', loyalty versus principle. There are some killer lines too. "If all I cared about was power", explodes Cooper accused of putting his own ambitions ahead of the party's. "Why on earth would I have joined the Lib Dems?"

The problem is that like its subject, Coalition doesn't quite know what it is - part House of Cards-style political intrigue, part comedy satire, it's two things yoked together that don't quite click. Veep has already probed the problems of being the second most powerful person in the country with a sharper stick.

Still, from Tuck's whirlwind of ineffectual bluster to Alistair Barrie's bluff Northen rebel, perpetually growling at being “handcuffed to an oil slick of Tories” there are no weak links in the cast. Phil Mulryne is a particular pleasure as the preternaturally smooth-faced, lightly smug young upstart with his eye on the main prize. Come to think of it, he looked worryingly familiar.

To 26 August, not 13 (0131 556 6550)