Britain has had its challenges recently – a stagnant economy, some hilariously catastrophic cameos at the World Cup – but there’s one area where it reigns eternal, and that’s in the field of quirky sleuths. Here, Britannia rules the airwaves, from Arthur Conan Doyle’s Sherlock Holmes to Benedict Cumberbatch’s version, via Inspector Morse, Father Brown and Miss Marple.A relative newcomer to the genre of ace case-cracker is David Mitchell’s Ludwig (BBC One, Thursday, 9pm), the lead character of which is a designer of puzzles turned accidental detective who now returns for a second series of cosy-crime, larking in suburban Cambridge.Mitchell first came to attention in the cringe-comedy masterpiece Peep Show. In many ways, Ludwig is Peep Show with added murder. Mitchell is once again sublimely awkward as John “Ludwig” Taylor, a nerdish genius with dreadful people skills and a talent for unpicking arcane crimes.He has a great foil in Anna Maxwell Martin’s Lucy, the go-getter sister-in-law whose search for Ludwig’s missing police-detective twin, James, drew the flailing hero into the crime-solving business in the first place.The mystery of what happened to James (who’s still AWOL) is teased out across the season. There are hints at a conspiracy at the local police force, to which John has been seconded after initially posing as James. There are indications, too, that James’s disappearance was motivated by his dissatisfaction with his life. Could it be that he wasn’t bundled off by nameless nasties but fled the drudgery of domesticity?Lucy is understandably upset. But there’s not much time for mooching, as each episode also features a satisfyingly crunchy one-off murder mystery. For starters there’s the case of a pensioner who cops a fatal scissors to the chest in a packed theatre. The only person to witness the death was the local MP (Fleabag’s Sian Clifford). But does she know more than she’s letting on?There’s lots of droll high-jinks as Ludwig sniffs around the crime scene. Lucy, meanwhile, goes behind his back, posing as a journalist to uncover the truth about her husband.[ Ludwig season 1 review: David Mitchell is perfect as nerdy sleuth in comic thriller stuffed with laughsOpens in new window ]The leads form a great double act: they have a fantastic fed-up chemistry, which is just the thing on a glum weeknight with autumn fast approaching. It’s a mystery how British telly so consistently comes up with new ways of telling the same story – the weirdo sleuth who grudgingly does the police’s job for them – but that’s a case Ludwig cracks with aplomb.