Mitchell is a short story writer. He strings short stories together and calls them novels. (Kipling did something similar.)
Mitchell is famous for doing voices. (Look I'm Kingsley Amis; look I'm Eric Fenby.) Here he's attempting to voice himself- or someone like himself (as a thirteen year old)- but he's still seeing life through genres- the sit-com, the ghost story, the school story. This is his most deeply felt book, but not his best.
All Mitchell's fiction is about man being a wolf to man. The awfulness is punctuated by odd, gratuitous acts of kindness. A hardnut (one of many) recommends the hero takes a bowie knife to the bully who is picking on him." I'd get sent to borstal," he protests. "Well, wakey fucking wakey," says the hardnut, "Life's a borstal!"