Our common culture – the huge audiences that tv, film and pop music used to attract – has evaporated. Politics is about the only thing remaining where we are all on the same page. It’s perhaps inevitable then that public reaction has become ever more febrile and volatile. Poll percentages now go crashing and soaring with a regularity that’s disturbing to those of us who can remember the prelapsarian age when we were the only people who gave a stuff about politics and that we were considered odd because of it.