Michael Chaplin’s A Walk on Part dramatises the fall of New Labour as documented by the diaries of ex-MP Chris Mullin. Following success both in Newcastle and at London’s Soho Theatre, the play has just transferred to the West End’s Arts Theatre, a 350 seater. I didn’t see either previous version, but it would appear that size is the only way the production has upgraded: after the opening’s vaguely jazzy digital start and Gary McCann’s promisingly metallic scenery, I was hoping that there might be something a little more technologically impressive than nine TV screens presenting the date and the odd political photo. Variety in approach was not, however, this production’s mainstay and, although limiting, this had two very real benefits.

Firstly, it was all to the good that, apart from discrete date changes on the TV background, no reference was made at all to the time passed, whether we skipped days, months or years. Despite the rapidity with which we jumped – often without connectives – between subject matters, the ease with which John Hodgkinson (as Mullin) narrated us through meant that the superficial sense of continuity he created managed to outweigh the fragmented reality of the script. Slickly directed by Max Roberts and seamlessly well-rehearsed, the contributions from fellow actors Norma Dumezweni, Tracy Gillman, Hywel Morgan and Howard Ward, as they imitated politicians and added dialogue to the otherwise (presumably) verbatim diary monologue, were beautifully choreographed and acted. Their complete focus and precision ensured our eyes never wandered from the central scene at hand whilst also injecting movement, energy and range into the play.

Secondly, to accompany the unkempt mad professor look, the ankle swingers, and the thrust forward pelvis and neck stance, Hodgkinson’s delivery was almost unfailingly upbeat. Even the supposedly rueful or thoughtful moments had a hint of the clownish (perhaps none more so than his laughable attempt to cry). I am inclined to be critical of this inability to metamorphose between emotions, especially when comedy is often the best prelude to tragedy, but Hodgkinson’s constant geniality and light-heartedness may well have actually saved the production. For, ultimately, no one wants to have two hours’ worth of a fundamentally depressing decline of ideals relentlessly rammed down their throats. This way, the audience’s predisposition to be cynical about politics was relieved by, but also restrained to, mere snorts of recognition or derision at good imitations of its politicians, or at the predictions about and references to issues which are now political hot potatoes.

Fast moving from the off, informative without being patronising and peppered with funnies, the production entertains right the way through. It does, however, miss perhaps the most crucial thing about a politician’s memoirs, especially one which came from a reign so inextricably linked with spin as Blair’s: presented as affability himself, Hodgkinson’s portrayal of Mullin doesn’t quite add up with the driving ambition he must have had. It seems like a safe bet to assume that Mullin would rather like this portrayal of himself and I’m not sure that’s all to the good.

A Walk On Part is playing at the Arts Theatre until 14th July. For more information and tickets, see the Arts Theatre website.