It’s not that she isn’t superb in Yield to the Night (and actresses have won Oscars for performances much inferior to this one) but I think she’s done more subtle and more original work than this.
The problem is that for Jim this is just a distraction, some recreational sex to keep his mind off his other problems. And he has lots of problems. His biggest problem is Lucy Carpenter. He’s crazy about her but she’s really out of his league. His other problems are a major propensity towards self-pity and self-dramatisation. Unfortunately Mary is hopelessly in love with him. And she can’t quite accept the evidence that he’s not that interested in her for anything other than casual sex.
Most of the movie concentrates on her experiences in prison, on the British equivalent of Death Row. The most interesting thing about the movie is the focus on her relationship with the various female prison warders, and in particular with MacFarlane (Yvonne Mitchell). Despite her tendency to shoot people Mary is a likeable rather vulnerable young woman and the warders grow quite fond of her. They get to know her very well, and they like her. Diana Dors wisely doesn’t resort to scenery-chewing. She downplays her performance, and that makes it all the more affecting.
The problem with this movie is the problem with all social problem movies. It’s essentially propaganda. Like all such movies it’s deliberately and shamelessly manipulative, willing to go to any lengths to advance its political agenda. And in this case it does so in a breath-takingly dishonest manner. The actual murder victim is dehumanised, depersonalised and marginalised to the point where she scarcely even exists, except in so far as she’s demonised to make us see her as the real villain.
None of which detracts from the skill of director J. Lee Thompson or the magnificent performance of Diana Dors, but I couldn’t help feeling a bit of a nasty taste in my mouth after seeing this movie. An extremely well-made and very emotionally powerful movie, but if you don’t buy its political agenda you may well feel uncomfortably that you’ve been used.