Mo Farah and Jessica Ennis-Hill were supposed to inspire us to be active. But the latest depressing figures will surprise no one who understands spectator sport The finding by Sport England that fewer adults in England are doing even half an hour’s moderate sporting exercise a week, with a particular drop among the poor, has dealt another blow to the grand claims made for the 2012 London Olympics. Tony Blair famously added the vote of the International Olympic Committee to other …