Benedict XVI once noted that in the early Church, converts were asked to renounce not just the Devil’s sins but also his pomp. Pomp partly referred to the ancient theatre where it was considered entertainment to watch men torn apart by animals. Centuries of horror in art implies that man has a cathartic need to witness other men suffering – and some of the ancient playwrights did at least try to squeeze a moral lesson out of it. Today, few bother. What is the lesson of Born to Kill (Thursdays, 9pm), Channel 4’s nasty drama about a teenage psychopath? Jack Rowan is very impressive as Sam, a 16-year-old model student who kills pensioners for kicks. I suppose the drama is exploring the old question of what makes a murder: nature or nurture?