If we were reviewing this 51-minute mystery/drama in 1937, when it was released, we might have been inclined to give it an 8 out of 10 rating overall. But it's about 80 years later, and as much as we may try to keep art in its own perspective, most of us are jaded by the slicker films produced since then.
The screenplay was an adaptation of the play "Double Error" by John Lee Thompson. When a screenplay is faithful to a play, immediate objections are raised. But "talkiness" and "static set" charges are not flaws to the entire audience - some may prefer dialogue to sensational effects. Welwyn Studios, where this was shot, had thin walls and inferior acoustics - originally it was a base for the production of silent films. It was susceptible to regular unwanted sound effects, speaking of effects, being situated near a noisy Nabisco shredded wheat factory and a noisy main-line railroad.
Colin Keith-Johnston as Martin turns in a fine nervous desperation performance, with only a couple of short lapses into melodramatic "moments of epiphany," staring too long to absorb shock, and leaving his mouth open a bit too long than modern audiences will tolerate as normal response to horror. Keith-Johnston makes us feel his pain, so his acting mission is accomplished, I'd say. A nice counterpoint to his well- and reasonably-sustained agony is Leslie Perrins' (Owen's) laid-back delivery.
There's an original plot. Keith-Johnston makes two dreadful discoveries as he careens into insanity, hence the title of the play, double error. We wonder how he'll fight back. Shoot Owen? Skip town? Shoot himself? We really don't know until the end, and we remain interested in his fate.
There's only one clear implausibility, having to do with the "window seat/chest," but to tell you about it would be to commit a "spoiler." Without it, I would have given the film a 9 out of 10.
It's directed by Walter Summers, who has a horror/mystery track record of 1920s and 1930s movies.
Suffice it to say this one is worth 51 minutes of your day. Unfortunately it's not available on VHS or DVD, and you must wait for some kind soul to upload it to You-Tube from the nitrate print, which still lives, parked in the British Film Institute files.