There is an important question hanging over Brexit, that has not been resolved, and I can't see how it can be resolved.
It's the Irish question.
The Republic is in the EU. Soon, the UK will not be in the EU. So there will be a border. On one side of the border is an area with EU tariffs, on the other with UK tariffs.
When the UK was in the EU, this was not a problem; Eu tariffs = UK tariffs. But what now?
If we had a single free-trade area, there would not be a problem, even with the UK outside the EU. But this isn't going to happen. The hard-liners in the Tory party would rather cut their own throats.
If we had free trade between Northern Ireland and the Republic, that would solve the problem, but then there's a trade barrier between Northern ireland and the rest of the UK, so that isn't going to happen, the DUP would eat Theresa May *and* Boris before they let that happen.
So we are going to have a tariff barrier between Northern Ireland and the Republic, with customs barriers and infrastructure and everything that goes with a land border. Except that we've promised we wont. The Republic won't wear it, and they get a veto, as part of the EU27.
It's a problem like a fidget spinner, with three sides that you keep turning. Why didn't The Powers That Be see this coming two years ago?