Sinn Féin, the second biggest party in the Northern Ireland Assembly, demanded a vote on uniting Ireland as the result was confirmed.
A statement from the party said: “The British government has forfeited any mandate to represent economic or political interests of people in Northern Ireland”.
Meanwhile Nicola Sturgeon said she would prepare legislation paving the way for Scotland, which voted to remain in the EU, to have a second independence referendum.
There’s also a threat to Gibraltar, as the foreign minister of Spain today called for joint-sovereignty of the Rock, as a stepping stone to Spanish ownership.
She said there had been a “significant and material change” to the UK that Scotland voted to remain a part of by a majority of 10% in 2014.
Mrs Sturgeon also accused her then rivals of telling Scots that the only way they could retain EU membership was to remain in the UK.
“As First Minister of Scotland I have a duty to respond to the democratic decision taken by the people of Scotland,” she said.
In the immediate aftermath of today’s result, she commented that it was clear that Scotland wanted to stay as part of the EU.
She said: “Scotland has delivered a strong, unequivocal vote to remain in the EU, and I welcome that endorsement of our European status.
“And while the overall result remains to be delcared, the vote here makes clear that the people of Scotland see their future as part of the European Union. Scotland has contributed significantly to the Remain vote across the UK.
“That reflects the positive campaign the SNP fought, which highlighted the gains and benefits of our EU membership, and people across Scotland have responded to that positive message.”
She concluded: “We await the final UK-wide result, but Scotland has spoken – and spoken decisively.”
Ex-SNP leader Alex Salmond said this morning that his party was likely to call for a second independence referendum.
“The sensible thing for Scotland to do would never be to leave the European Union,” he said in an interview with Sky News.
Asked if he thought Nicola Sturgeon would now push for a second independence vote, the former first minister answered: “Yes I do”.
Harry Potter author JK Rowling said she expected another Scottish independence vote, tweeting: “Scotland will seek independence now. Cameron’s legacy will be breaking up two unions. Neither needed to happen.”
Declan Kearney, a spokesman for Sinn Féin, said: “This outcome tonight dramatically changes the political landscape here in the north of Ireland and we will be intensifying our case for the calling of a border poll.
“The British government as a direct result have forfeited any mandate to represent the interests of people here in the north of Ireland in circumstances where the north is dragged out of Europe as a result of a vote to leave.
“We now have a situation where Brexit has become a further cost of partition, a further cost of the Union and Sinn Fein will now press our demand, our long standing demand, for a border poll.”
Irish finance minister Michael Noonan said earlier this week that the estimated Brexit-related hit on the Irish economy of as much as 1.6 percent of GDP would be “containable”.