At what stage in the writing process does Ruth Rendell decide to wear her Barbara Vine hat? Pseudonyms always signify something; a change of heart, a change of pace, a reputation showing too much mileage. But, even under her own name, Rendell is the most versatile writer in contemporary crime. She is also prolific, with a meaty series of TV adaptations to boost her sales and yet there’s no hint, so far, that she had outstayed her welcome.

Julian Symons (who has confided elsewhere that he baulks at being called a doyen of the genre, so I’ll refrain) suggests that in the Vine novels ‘Victorian skills are put at the service of a modern sensibility, skills given first to creating a plot and then shaping and styling it in a way to baffle readers and keep them turning pages’. He could have a tiny point there, although excepting A House of Stairs, which drew nourishment from a Henry James novel, I can detect no specifically Victorian cast to Vine’s plotting. There’s no straightforward detective work (although the Rendell books also often dispense with the boys in blue). Crime usually results in punishment (although the innocent suffer along with the guilty). The essential difference between the Vine and Rendell books – one which, I suspect, steals up on the author,