The Third Skin was John Bingham's third novel, appearing in 1954 (in the US, the paperback edition was called Murder is a Witch). It's a little-known book, having received only limited coverage over the years. This is surprising, because Bingham's first two novels were well-regarded, and this one is certainly up to standard. It also marked a departure from his early books, which contained much fictionalised autobiography, and were narrated in the first person.
This is a story about a naive and weak-willed youth, Les Marshall, who works in a newspaper office and gets himself mixed up with a gang of youths with disastrous results. Les falls for Hester, the girlfriend of his pal Ron Turner, and finds himself lured into a trap, collaborating with Ron on a burglary which goes tragically wrong. And gradually the spotlight shifts away from clueless Les, and on to his mother, the resourceful widow Irene. It's a study of character as well as of crime, and as so often with Bingham, it offers an account of relentless police interrogation, this time with a sympathetic and well-rounded presentation of the lead detective, Vandoran.
The book is discussed in Michael Jago's enjoyable biography of Bingham, The Man Who Was George Smiley, and Jago makes the point that Bingham really didn't know anything about teenage gangs. That's true, and arguably it's a flaw in the story. But I don't know much about gangs either, and really I felt that Bingham's lack of first-hand knowledge wasn't a significant disadvantage. Hester, presumably the witch of the alternative title, is portrayed in a fairly superficial way, but Les is all too believable. There is also some excellent comedy in Bingham's presentation of Irene's friends, Gwen and Frederick Perry.
Although Jago doesn't mention it, I feel almost sure that Bingham's original idea for the story came from the circumstances of the Craig and Bentley case, in which a weak young man was hanged for a murder committed by his pal. Derek Bentley was, to an extent, the model for Les Marshall. The way he develops the idea, and in particular the passages dealing with Irene and her circle, is pleasing and reasonably original. As a result, suspense builds all the way to the end of the book. This is an under-rated novel, which I was very glad to read.