As the author herself points out, there are close parallels between this story and the stories of Evans and Christie, but it is a work of fiction and, I think, should be treated as such. To do otherwise is to miss the point. I have no idea what was going on in the minds of the arresting officers and it has no relevance to this story because Davies and Backhouse are not Evans and Christie. I think giving the role to an established and well liked character is very interesting, much more interesting than using a stereotypical bad cop bullying a confession out of someone who was unfit to plead. This device, as well as adding depth to Stratton's character, raises many difficult questions about our system of justice.
Does it work as a detective story? Yes and no. We know the outcome of the detective puzzle but the characters and the world they live in are strong enough to sustain our interest. Davies and Backhouse are both very strongly drawn, Backhouse, in particular, being a creature of nightmare, plausible yet deeply horrible. Life in the early fifties becomes very real - its dreariness, narrow-mindedness and the sense of disappointment that victory and the end of the war did not bring universal happiness and lightness of being, just tiredness, guilt and regret. It reminds us how stratified society was in those days - you live in your own small world and, on the whole, do not move out of it. If you do, you become vulnerable.
I have enjoyed the other books about Stratton and this one maintains their high standard, but it is, although engrossing, a less comfortable read. This is why I have given it only four stars instead of five, which is perhaps unfair.