This whodunit is fun. It is well structured and being very much on the lines of a television drama, cleverly staged so that the action goes seamlessly from scene to scene, changing from the morgue to the police station to the beach.

Women are being killed. A serial killer is at large. There is an obvious suspect but when he protests his innocence it is utterly convincing. Detective Roy Grace (Bill Ward) is perplexed. Sometimes he gets angry and you can tell when that is because his voice gets louder and he starts pointing with his arm outstretched.

His love interest is Cleo Morey (Laura Whitmore), She works in the morgue and is usually cool as a cucumber but sometimes she gets upset and you can tell when that is because she screws up her face.

There is a lawyer for the chief suspect played by Charlotte Sutherland. You can tell when she is annoyed because she puts her hand on her hip and covers her eyes with her hands.

This is a masterclass in cod acting. It’s all highly entertaining from start to finish. It’s not difficult to guess the twist in the plot but that doesn’t spoil it. It’s like the satisfaction you get from doing the easy crossword. No one is method here, darling. You doubt whether anyone did any research in a morgue or a police station.

Why bother, we have all seen the tv programmes where miraculously someone finds footage on laptop that gives you just the evidence you need so that one of the characters can say: “Take a look at this, now freeze that frame....”

The nearest anyone gets to naturalness is Gemma Stroyan as police officer Bella Moy, though even she has to resort to the cliches in the script like the one above.

Stephen Billington as Brian Bishop, chief suspect in the murders, gives a relaxed performance and Michael Quartey as Detective Glenn Branson gets quite a few laughs but broadly speaking there is as little depth in the acting as there is in the plot. It’s a lark, it’s not meant to tear anyone’s soul out.

The audience enjoyed itself, the villain is caught in the end and the principals live to fight another day - or be cast in yet another of Peter James’ murder mysteries. The main mystery being how he keeps getting away with it. An amusing night out.