If Scotland votes Yes to independence it would prompt a crisis for Northern Ireland unionists and could spark political instability, an academic has said.
Generations of migration between the two regions have created close cultural and historical links.
In places, the gap between the two coasts is hardly 20 miles.
Loyalists fly the Scottish saltire every summer during their marching season celebrating the 1690 victory of William of Orange over Catholic King James II during the Battle of the Boyne.
Professor Peter Shirlow, an academic specialising in conflict resolution at Queen's University Belfast, said a Yes vote next month would be a "shock to the whole body politic of the UK".
"It would be a point of instability, it would be a sense that we are moving in one direction, which is the break-up of the UK, that would lead at some point to unification (with the Republic of Ireland).
"Sinn Fein would be energised by that, which would add more to fractures we have in Northern Ireland.
"We have a political institution which is not evolving, going from one crisis to the next. A Yes vote would most certainly be a crisis for unionism."
Recently Sinn Fein president Gerry Adams said the political institutions faced their greatest crisis since 1998. Stormont First Minister Peter Robinson responded by warning that an impasse over welfare reform was the most likely issue to force a collapse of the five-party ministerial executive.
Professor Shirlow said both sides would be affected by a Scottish Yes vote.
"A Yes vote would be a shock to the whole body politic of the UK. Anything which is constitutional would be felt quite strongly here.
"Out of the four countries that make up the UK, it would be an issue here. This is not something that is on everyone's lips but if the vote goes Yes, it might be."
Scotland's First Minister predicted this week that the independence referendum will attract the biggest turnout in the country's political history. Alex Salmond urged political gamblers to put their money on an unprecedented 80% turnout. The former racing tipster also said he expected people who had never voted before to be a "major factor". The pro-UK Better Together campaign accused Mr Salmond of "desperation" ahead of the vote on September 18.