I ask a question I feel sure he'll dodge: about the trial of Charles Saatchi's former housemaids and the revelation that his ex-wife, Nigella Lawson, used cocaine. Her fans have rushed to her defence: 'Team Nigella' is used as a hashtag on Twitter and even sprayed on city walls. Is the Prime Minister on Team Nigella? 'I am,' he says. 'I'm a massive fan, I've had the great pleasure of meeting her a couple of times and she always strikes me as a very funny and warm person. Nancy [Cameron's nine-year-old daughter] and I sometimes watch a bit of Nigella on telly. Not in court, I hasten to add.'