For many, Friday marks a departure as mind-boggling as it is heartbreaking. But the path to Brexit was laid years before the referendum

As a previous Tory prime minister trying to find his way through difficult times once said: this is not the end. It is not even the beginning of the end. But it is, perhaps, the end of the beginning.

Brexit is hardly complete. The last-minute nature of the UK’s trade deal with the EU and the fact that it barely covers whole swaths of the economy – financial services are a good example – means some negotiations will have to grind on. The new bodies set up to arbitrate between the two sides will soon have work to do. Northern Ireland remains part of the single market for goods and will be enforcing EU customs rules, the most vivid example of the deal’s contorted provisions, which may have no end of political consequences. Certainly, given that public opinion in Scotland now suggests unprecedented levels of support for independence and that elections to the Scottish parliament will take place in May, what Brexit means for the increasingly fragile union between the UK’s four countries will now start to become clearer.