The Special Relationship, BBC Two

The double act between screenwriter Peter Morgan and his favoured leading man Michael Sheen has given us some of the most teasingly enjoyable dramas of recent years, but how much genuine insight they've given us into Tony Blair or New Labour remains a moot point.

Of course, the unbridgeable gap between fact, fiction, the known and the unknown suits everyone. Morgan and Sheen have hit upon their own nifty brand of docutainment (a genre which also includes their gripping but brazenly fictionalised Frost/Nixon), where they can push the imaginative envelope almost as far as they like because a definitive version of events, if anybody were capable of creating one, will never be made public. Tony Blair gets to tell his own version in his autobiography, hilariously garlanded by quotes from the Queen which Morgan claims he invented but Blair insists are authentic regal utterances, while Alastair Campbell can keep up his grumbling barrage of diversionary fire while he fades into a long twilight. It's like an alloy of fact, fantasy and interpretation, where nobody knows where the boundaries lie and, if there's any blame to be apportioned, nobody knows where it went.

Dennis Quaid has brought a gravelly weight to the Clinton role which lends him a sense of inner conflict which Sheen's Blair lacks, though that may merely reflect the likelihood that the more layers you peel away from Tony Blair the less you're going to find inside. On the other hand, Quaid doesn't quite nail Clinton's magnetic down-home charm, while Sheen slides effortlessly back and forth between Blair's puppyish gregariousness and his shining-eyed, visionary mode. Rather than playing the President as merely a philandering blarney-merchant, Quaid has equipped him with the kind of brutal pragmatism without which nobody could reach the summit of American politics.

The supporting players are a treat too. Helen McCrory (pictured left) perfects her pithy portrayal of Cherie Blair, while Hope Davis (pictured above right) is brilliant as a steely Hillary Clinton, focusing on her own long-term political ambitions while trying to drag herself clear of the quagmire of her husband's sexual weaknesses.

• Watch The Special Relationship on BBC iPlayer
• Read theartsdesk's Q&A with Michael Sheen