Psychological Horror film, most likely British

[zelo1954]

Pretty sure it is British. Genre would be psychological horror. Can't remember when I saw it (TV) but it has to be 30 or more years ago I would say. Probably b&w. Know nothing about the actors.

Now then something about the plot:
Star was a university doctor/professor who was developing a potion with which he was treating psychopaths. One weekend he invited three of his students to his home ostensibly to "discuss matters psychological". The real reason was to test the effectiveness of his potion on three of his psychopathic patients. His idea was that each patient would be allocated to one student - and we see what happens. I'm certain one of the psychopaths was called Bostyn and another was something like Kessler or Kesselring - and this one had a major hang up about his facial appearance. I think at least two of the students were killed.

Any ideas?

[GRAEME]

This is an edition of the TV anythology series "Thriller": A Killer in Every Corner starring Patrick Magee and Don Henderson.

[zelo1954]

Excellent Graeme. Thanks so much for that. I found the most memorable actor in this film was Don Henderson who played Bostyne. He was ideally suited for these parts. Checking the film on other sites I find two strange things:
1. The plot was supposed to be about a potion to *cause* people to murder. I thought exactly the opposite.
2. There were supposedly 2, not 3, students. I'd have staked my life on 3.
This is one of three memorable films for me, the other two being 'The Wicker Man' and 'The Stranger Left no Card'.

[GRAEME]

There were three students! Two girls and a boy - they are on the train at the start together.

Max Wall is also good as a deranged psycho-killer the Prof is experimenting with.