I think this film resembles "Psycho" in many ways. i.e. lonely young man, (damaged mentally by his parent -- in this case the father instead of the mother), goes around murdering young women in a very macabre manner. One could almost call it a British/Technicolor "Psycho".
Shearer is third billed and yet is only in a few key scenes, which mirror Janet Leigh's part in "Psycho" . (I checked their ages and Leigh was only 18 months younger than Shearer). Again mirroring "Psycho" - Shearer is killed off very early into the picture. Her death scene is less shocking than Janet Leigh's, in that we don't see any blood; we just see her horrified face through Carl Boehms amateur cine camera lens, the knife getting closer and closer; we see her screaming; and then the (studio) camera pans away to the ceiling, with only screaming being heard.
There is a brilliant bit of business early on in this film with brilliant character actor Miles Malleson going into a magazine shop and buying "under the counter" porn. He says "A friend of mine tells me you sell views?" When passed the book of "Views" (obviously of young ladies in various poses) -- he says, "Oh - how much for this one??" and "How much for that one??" and then finally -- "Oh! How much for whole book?" It's so funny -- and brilliantly played. As he leaves the owner of the shop says, "Well he won't be watching the cricket on TV tonight!".