If ever a TV show encapsulated English humour - wry, self-deprecating, sometimes macabre - this show did. The humour here is often so understated you can miss it completely: a man who fell to his death is described by a relative as "very down-to-earth... in a manner of speaking"; describing the social mores of Flaxborough Inspector Purbright says the inhabitants can tolerate anything but "flagrant unostentation", while two roads in the town are named 'Edward Crescent' and 'Abdication Avenue'.
I think Richard Harris made a genuine attempt to capture the idiosyncracies of Colin Watson's fictional world, but with only a handful of 50-minute episodes to do it in, a great deal is lost. Thankfully, the books are now, in 2018, being re-issued so they can savoured once more - they are not to be rushed like an airport thriller. The series also stands as the final achievement of BBC producer Martin Lisemore. In a too-brief career Lisemore gave us (among others) the 26-episode adaptation of Anthony Trollope's 'The Pallisers' (1974), and 'I, Claudius' in 1976 - classics by any standard. He was tragically killed while working on this project.
Anton Rodgers makes a great job of Purbright - patient, placid, dogged, and with a wicked line in penetrating interviews with suspects. Christopher Timothy (not yet James Herriot) is the eager young sidekick who hates dead bodies, but has a way of inviting unwitting confidences as he appears so naive.
If you decide to give this series a try, my advice is: listen carefully; be patient while the story develops, and; be prepared to ignore the dated technical standards and studio settings. It's not perfect, but still worth watching.