The result is an overarching ‘what happened to James’ mystery, accompanied by several mini case-of-the-week murders, each of which John-as-James approaches using puzzle logic. Every episode winds up with the handful of suspects gathered in one place while John reveals the killer, who, helpfully, usually holds their hands up and volunteers an ‘it’s a fair cop, guv’ confession.
It is, let’s be frank, a preposterous premise and one that never explains why, if James was in such immediate danger that he had to disappear instantly and without a trace, the brother pretending to be him in public for several weeks remains unmolested. But who really cares. It’s nice. It’s unbarbed. It’s unchallenging, and it features guest appearances from Felicity Kendal and Derek Jacobi, like all TV broadcast in the months leading up to Christmas should.
The role is precision-engineered for Mitchell. He plays it buttoned up, anxious and exasperated, like he plays every character, from himself on Would I Lie to You to (probably) Police Officer Panda in Peppa Pig. The result is lightly comedic and quite charming. Introvert John is a less-than-slick operator whose impersonation of his more outgoing brother is always threatening collapse, while his uniquely logical perspective on the world makes him a whizz at deductions. Imagine Sherlock Holmes with no self confidence, or Mole from The Wind in the Willows with some, and you’re about there.
John’s rationality isn’t so much a unique selling point as something that helps to decide whereabouts to file him in the TV detective hall of fame. (Left at House, a good few rows behind fellow crossword-lover Morse). His interest in process rather than motive (“If we can demonstrate who did it and how, then the why doesn’t really matter.”) sets him somewhat apart, but otherwise, he’s the latest in a long line of socially inept but mathematically brilliant British sleuths.
Maxwell Martin is very good as sardonic, clever Lucy, and the supporting cast features likeable faces Dorothy Atkinson, Dipo Ola, Sophie Willan and Izuka Hoyle, with brief appearances from Ralph Ineson as the potentially shady top brass, Chief Constable Ziegler.
The cases themselves are neither stupidly obvious nor devilishly clever, and the crimes investigated all make for unthreatening viewing. You’ll have no nightmares here. It’s formulaic and lightly funny (depending on how hilarious you find bad driving), and were it not for the star power of Mitchell and Maxwell Martin, might well be seen otherwise unchanged airing on a weekday afternoon instead of in the 9pm slot.