Grisham is the undoubted master of the taut courtroom thriller. But on the evidence of this, he really should stick to writing for adults.

Theodore Boone is clearly aimed at the teen (or even pre-teen) market. The book’s eponymous hero is a precocious 13-year-old in a small American town who is obsessed with the law, and knows every lawyer, judge and policeman who frequents the town’s small courthouse.

When a big murder trial starts, Theodore finds every excuse he can to skip school and sit enthralled in the court’s public gallery watching proceedings.

But then it transpires that a schoolmate’s cousin has information about the murder that could change the course of the trial. And Theo is the only person he trusts to do anything about it.

The courtroom scenes are handled with all Grisham’s customary aplomb. But sadly he seems to know nothing about the way 13-year-old boys act and think. The character of Theo is wooden and unconvincing – he’s the kind of 13-year-old Mary Whitehouse would have clucked over approvingly. And the most interesting relationship in the book, Theo’s friendship with a girl in his class, is barely sketched in. A disappointment.