“There is one other possibility, that is to have that some UK citizens may maintain citizenship of the European Union and others won’t. And this is a bit of a provocation… It is… Nothing prevents a part of the United Kingdom to stay and another part of the United Kingdom to leave. We have a precedent with that; it’s called Greenland. We have the case of one member state where part of its territory left the European Union and another part stayed. So, in principle, nothing will prevent for the territories, for example, of Northern Ireland and Scotland to stay in the European Union, and for the rest of the territory of the United Kingdom no longer to be part of the European Union.
“Of course, this will be complex to organise in practice, it will require a border inside a member state, because it will basically mean that Scotland and [Northern] Ireland will remain part of the European Union and part of the United Kingdom. But it will not be impossible.
“Still, it will be again very problematic in political terms, and the consequences of it will make it difficult. If we think about it… I think, on the one hand one risk will be economic—for the UK—because naturally you will have… I will say for Scotland and Northern Ireland, it would be extremely positive. They will attract lots of investment and companies that will locate in those territories because they could benefit from both those markets. But of course for the rest of the United Kingdom it will be even more dramatic because there will be economic mobility to that part of its territory.
“For the European Union, the difficultly will be that if this will take place without the UK formally leaving as a state—because part of its territory will stay, in the same way that happened with Denmark and Greenland—it will mean that the representation of that part of the territory would be made by the UK government; not by the Scottish and the Northern Ireland governments. For this to be done, without leaving and then coming in as Scotland and Northern Ireland to be then in terms of state secession, the representation of this part of the territory will have to continue to be done by the United Kingdom central government.
“Of course, there will be the possibility to leave as [the] UK and come in as part of the UK. That will be another alternative.”