I wonder how the local PBS chooses which old movies they use to pad out their late-night schedule during pledge drives. Length seems to be a primary consideration alongside availability; Green For Danger is just a hair over ninety minutes long, which makes it a good companion to Dinner At The Ritz, which is a bit under. Together, the two British-made mysteries fill three hours in relatively unobtrosive and mildly amusing fashion.The "amusing" part comes from Alistair Sim, who as Inspector Cockrill doesn't quite bumble through his investigation of a murder (or is that a pair of murders?) at a country hospital during the Blitz, but is rather casual going about it. A patient died while under anesthesia, and when a nurse publicly claims she has proof it was murder, she herself is bumped off. Hence the investigation.
It's immediately obvious that this is adapted from a mystery novel in the Agatha Christie vein. There's a certain structure that must be adhered to - the carefully limited field of suspects, the inquisitive investigator who basically announces who the suspects are and learns more from observing behavior than forensics, and the improbable gathering the suspects to recreate the crime and thus prove the guilt of one. It's a venerable structure, although it has come to seem quaint now; even when it is used on Monk, it frequently gets mocked. There's also narration, both as bookends and within, to describe Cockrill's thought process. This narration is, of course, despite being presented as an official communication being written after the fact, utterly vague until such time as the mystery has been solved.
It's an able mystery, if not an exceptional one. Christianna Brand's characters have just enough differentiation to give them motive, and the direction is middle-of-the-road.It's a cozy mystery, no more and no less, though notable for being set during an un-cozy time.