A Study in Terror (1965)

A story that puts the fictional Sherlock Holmes (John Neville) into a real life historical setting, namely Whitechapel, on the trail of Jack the Ripper.
It must be a difficult thing to make Holmes seem ineffability clever without also being arrogant or smug; Neville manages it some of the time, but his sleuth definitely crosses over into the less likable sphere from time to time.
With the exception of Carry On queen Barbara Windsor, who gets colourful attire and some actual characterisation, the prostitutes are blank tools. The city fares better, with dingy alleyways and rain-soaked cobbles. The sound of night-walking heels on the latter is suitably atmospheric.
The murders are violent for the era, even when they aren't shown directly; the most unsettling of which is surely the lengthy POV scene that puts us into the killer's world while simultaneously masking the perpetrator's identity.

2½ maxims out of 5