If he refuses a referendum that Scots have voted for, there would be no lawful way to leave the UK. The implications are huge
Three weeks from now, if opinion polls are correct, the Scottish National party will win another term as Scotland’s government. It will do so armed with a mandate to hold a referendum on independence. Elections, of course, retain a glorious capacity to surprise. But it is a mark of the slovenliness of Boris Johnson’s government that its strategy for avoiding the breakup of the United Kingdom is now reduced to two words: fingers crossed.