Ruth Rendell’s book, A Judgement in Stone, is widely considered one of her best, and rightly so – at first sight, it might be a country house whodunit, or else a police procedural, but really, it’s neither of those things. For a start, the murderer is identified in the very first line.

In this new adaptation for the stage, that doesn’t happen, or rather it doesn’t happen outright: it’s fairly obvious, pretty early on, who is responsible for the murders of the Coverdale family in their own living room. The joy of this for the veteran mystery-lover, then, is watching the layers of detail be applied and the clues add up to the final reveal. If you turn up to A Judgement in Stone expecting to be surprised… well, you probably won’t be. But there are other things to be done with crime stories than insisting they be thrilling – and Ruth Rendell and her adaptors Simon Brett and Antony Lampard, as well as director Roy Marsden, all know this.

So on top of the story of who killed the four Coverdales, this is a comedy of manners, with and plenty of poking fun at snobbery in all its forms. The Coverdales’ awkward and reticent housekeeper-with-a-dark-secret, Eunice Parchman (Sophie Ward), is arguably the main character, although the whole thing veers dangerously towards an ensemble piece – and Ward has the most difficult job of holding the whole thing together across two timelines, in as few words as possible. The further through, the better a job of it I realised she was doing. Andrew Lancel and Ben Nealon seem to have come from the audience stand-in school of fictional detectives, but that’s okay, and Rosie Thomson and Jennifer Sims are far more interesting as naïve but well-meaning Jacqueline Coverdale and her step-daughter Melinda. That said, it often feels like they were given the most to do.

Pace-wise, A Judgement in Stone skips through at a great trot: fast enough to keep you guessing, but not so fast to give you whiplash. If anything, the ending feels like it dissipates too quickly after two hours of build-up – another five minutes would be golden. It feels… it feels well-engineered, more than anything else. The trouble with both this brand of classic mystery is that it has a tendency to focus on puzzle mechanics to the exclusion of character and depth. But for an adaptation of an original so up-front about its “solution” and so focused on its characters’ feelings and fears, to translate it into a straight-up whodunit feels like a missed opportunity.

Photo by Mark Yeoman

A Judgement in Stone runs at King’s Theatre, Edinburgh, until Saturday 18th February.