I meet David Nicholls for coffee at his house one weekday morning. We talk about Henry James and he tells me that he read Portrait of a Lady last year. The novel obviously had an impact on him as he quotes from it in his latest, rather wonderful novel, Us. I want to get to the nub of what he enjoyed about the novel this time round which had eluded him in the past. He is just about to tell me when a nice man from a security firm pops his head round the door.