My guest in this week’s Book Club podcast is the novelist Nick Harkaway, whose new book Karla's Choice sees him pick up the mantle of his late father, John le Carré, in writing a new novel set in the world of George Smiley. He tells me why, having spent a career trying to put clear blue water between his own work and that of his father, he’s now steering in the opposite direction; about growing up with Smiley; about his relationship with the man so many outsiders have seen as secretive and opaque; about seeking advice from Stephen King’s son, Joe Hill; and why moving from his own style to that of his dad is just a ‘turn on the dial’.