Professor Edgar Morgenroth:

If I can come back in on the question of what would hold Northern Ireland back, in the event of there being a united Ireland, there would obviously be all sorts of alignment and there could be benefits from that. There is one aspect where there would definitely not be a benefit and that is with the current economic integration with the rest of the UK. Costs will arise in terms of additional trade costs and so on. We have seen this in relation to the Brexit debate and the need for a special arrangement for Northern Ireland. In the event of unification, there would be a separation of the two economic systems and that will come at a cost. These costs would eventually reduce as Northern Ireland integrates better with the rest of Ireland but initially they could be quite substantial. In fact, they would initially be bigger than the integration effects with the rest of Ireland. Eventually, that will be wiped out but it will certainly be an issue initially.