MV> I say what I said two years ago: if they want to go let them go.
What I also said, but perhaps not here, is that the UK not wanting to be in the EU customs union AND not wanting a "status aparte" for Northern Ireland AND not having a visible border between Northern Ireland and the Republic of Ireland is a mission impossible.
If the UK is not in the EU customs union, there has to be a border somewhere and it can not be invisible.
Eventually the people of Northern Ireland will to have choose between a border in the Irish sea or a border between them and the Republic. It is one or the other, not a bit of both.