If Scotland leaves the UK, the NI Unionists will explode. Northern Ireland is closer to Scotland than England both in culture and proximity. Right now, NI citizens have a better deal in the UK than non-NI citizens, so they might not see the need to join the Republic, but watch this space, right?
It gets interesting if Scotland joins the EU. That would leave NI rather isolated. I'm a complete outsider, but it's hard for me to imagine a United Ireland. I can imagine an independent NI, with special relationships with the Republic of Ireland, Scotland, and what's left of the UK. And independent NI isn't a tiny country, by European standards.
> independent NI isn't a tiny country, by European standards.
At 1.8M people, it would be larger than Cyprus, Malta and Luxemburg, so yeah.
It is an interesting possibility, but would it make any sense?
People who want a united Ireland wouldn't like it, and people who want it part of the UK wouldn't either. Both may like it more than the opposite alternative though.