The Hypnotist is a 1957 British film, which in the US was given the title Scotland Yard Dragnet. I don't think The Hypnotist is an ideal title, but the American alternative is terrible. Thankfully, the film itself is pretty good. It doesn't seem excessively stagey, even though it was based on a play by Falkland Cary, who apparently was an obstetrician before he turned to delivering work for the theatre.
Paul Carpenter plays Valentine Neal, who is involved in a flying accident and suffers an inexplicable psychological trauma as a result. His fiancee, Patricia Roc (who was a very celebrated actress in her day) finds the medics stumped by his condition, so she seeks help from a family friend, Dr Pelham (Roland Culver) who is an expert on getting to the root of psychological problems.
The murder mystery that develops from there is straightfoward in some respects,but I felt that the director, Montgomery Tully, made pretty good use of the material. Admittedly, an interlude in which our hero loses his memory and gets involved with a pretty girl he meets in a jazz club seemed more like a commercial for Chris Barber's Jazz Band than something that contributed to the plot, but the story held my attention better than many with a much bigger budget.
In researching the film, I found that Carpenter, sadly, died quite young and in rather tragic circumstances. On this evidence, he wasn't a top-notch actor, but I see that he took a lead role in a film of Julian Symons' The Narrowing Circle - a book that I didn't know had been filmed. Sadly, no DVD appears to be available. I assume it sank without trace, but if anyone knows anything about it, do please let me know.
One actor I did recognise was William Hartnell, who played the Scotland Yard cop in his customary grumpy manner. A few years later, of course, he would achieve a kind of immortality by becoming the very first Doctor Who.