Every few years in a general election, Britain gets the chance to throw the rascals out. On Thursday, it gets the chance to throw itself out while leaving the rascals in. Uncertain leadership has obliged the country to make a choice that better diplomacy might have rendered unnecessary.

The referendum has also forced our political class to clarify its thinking. That overdue enlightenment has come at a price. The tone of the debate has at times turned ugly. The murder of Jo Cox MP, one of the brightest and best of the 2015 intake, is a terrible tragedy that leaves bitterness in its wake. That said, politicians must beware of the demagogy that afflicts some in Europe and America and which British politics has hitherto