When I’m speaking to people who know nothing about prisons, I often start with an entertaining mind game.I ask people to imagine that they are on the board of a company with a turnover north of £6bn a year. The company makes widgets. The widgets have a failure rate of 56 per cent after 12 months. What would you do? ‘Sack the management’ is the predictable and not unreasonable cry in response. Well you can’t, I tell them. I’ve just described His Majesty’s Prison and Probation Service. The widgets are the offenders, and the failure rate is the number of male adults who reoffend after a year or less inside. Why this organisation fails so badly would take a whole book. So I wrote one. But I want to focus on one issue that is so scandalously bad and so morally awful that there is only one public sector organisation that could conceal it behind the high walls, literal and figurative of our collapsing prisons: staff sickness.