This film, actually an episode of the British anthology "Thriller" has been little seen and tends to be little regarded, with the comment above more positive than most. I actually think it is excellent and remarkably thought-provoking. If you are fortunate to see it you might be pleasantly surprised.
Oxford Professor Michael Lane is indulging in an affair with one of his young students, Stella. They want to be together, but how? Without Stella's knowledge Michael kills his wife, setting-up an elaborate scheme that makes it seem she has been killed by an intruder while he was meeting a colleague. He is delighted when the plan seems to work, with the police none the wiser.
However somebody knows his secret and he starts to receive disturbing blackmail notes, with the words cut-out of newspapers. His affair continues but he becomes more anxious and suspicious. These suspicions lead to another murder but the notes keep coming. Can he silence his accuser?
This is a fine, very intriguing story. The small cast allows the few characters to be very well-drawn. There are interesting insights into religion rarely seen in "Thriller", with the Professor a confirmed non-believer and his wife a devoted Catholic. The themes of anxiety and suspicion are very well-developed. All the main cast give strong performances. Patrick O'Neal is very convincing as the Professor. Gerald Sim plays Petersen, who exudes gentlemanly decency, although that doesn't stop Michael suspecting him as well. Quite possibly the best display is by Gary Watson as the enigmatic Inspector Rush. Rush appears to suspect nothing but it is evident he knows much more than he lets-on. Angharad Rees and Michael Kitchen play Stella and George (another student) capably and later became very frequent television faces.
Typically for "Thriller" the direction by John Scholz-Conway is splendid but probably even better than normal.There are some very poignant shots of a photograph of the Professor and his wife. The movie version - the only one likely to be seen - has the benefit of some very chilling music at the beginning and end, while Laurie Johnson's music during the action is powerfully unsettling as always.
The ending is absolutely extraordinary. For me it an absolute masterstroke but it is fair to say others have found it quite incredible. It certainly will get you thinking about the vagaries of the human mind! Could such things happen? Watch .. and judge for yourself...