All political careers end in failure — it’s the dynastic death throes you want to watch. The leader departs with a wave and a whimper; the acolytes slither in blood and guts and gore. And so it was with David Cameron. While he made a dull speech in the drizzle outside Downing Street and his wife wore a nice dress, the Chumocracy he had presided over for 20 years and more tore itself apart behind the scenes.