I have just seen this film for the first time, and I must say, it's staggeringly good.
It was light years ahead of its time, and seems ever so relevant today, like it could be from today's headlines. It's not dated at all, and has lost none of its punch.
I was definitely pleasently surprised. It may not be a pleasent film to watch, but it is very well done.
I watched this on a Blu-ray with a beautifully restored picture. The Blu-ray is all-region and made by a company in UK, where the film is called "Never Take Sweets From a Stranger" ( https://www.blu-ray.com/movies/Never-Take-Sweets-from-a-Stranger-Blu-ray/283536/ ). Ironically no one says "sweets" in the movie, as it is set in Canada.
The film definitely feels modern. The strong ensemble acting, the thriller elements, and the social indictment aspect, all make me feel this would be something Clint Eastwood would tackle if he made this kind of film today. The film makes me think of Changeling (2008) or Mystic River, in which we not only get a crime story, but also powerful depiction of the social mores and the attitude of the time.
Hammer should have gotten Ken Russell and Roman Polanski into their stable and taken a few more chances in the late 60s and early 70s. Maybe they would have lasted a bit longer. Imagine if Repulsion, The Fearless Vampire Killers, Rosemary's Baby, The Devils or The Wicker Man had been Hammer films. They went to the Dracula/Frankenstein well once to often, adding only some boobs and lesbian vampires, rather than making more artful and serious movies. It cost them.
*ironic I mention Polanski considering this film's content, eth?