Voters who wanted Britain to remain in the European Union (EU) have started a petition calling for a second referendum, and it already has more than 62,000 signatures.
It calls on the government to "implement a rule that if the remain or leave vote is less than 60 percent based on a turnout less than 75 percent, there should be another referendum".
The UK Parliament will consider a petition for debate if it reaches 100,000 signatures.
Meanwhile, Scotland's leader says the country still sees its future firmly in the EU, raising the possibility of a new independence vote and the possible dissolution of the United Kingdom.
Scotland voted by a margin of 62 percent to 38 percent to remain in the EU, putting it at sharply at odds with the UK as a whole, which voted 52 percent to 48 percent to leave.
"Scotland has delivered a strong, unequivocal vote to remain in the EU, and I welcome that endorsement of our European status," Scotland's First Minister and SNP leader Nicola Sturgeon said.
One key reason Scots rejected independence in a referendum almost three years ago was because it would mean leaving the EU too. Some Scots who wavered, but eventually voted to stick with the UK in 2014, may now prefer to join the secessionists.
Splitting Scotland from the UK would end three centuries of shared history, upending another successful economic relationship shortly after the impending divorce between Britain and the EU.
Ms Sturgeon did not mention a new independence vote in the immediate aftermath of the Brexit result, but her Scottish National Party has repeatedly indicated that if the vote was divergent it would want another vote on Scotland's independence.
In Northern Ireland, 56 percent voted to remain and Irish nationalist leaders there have called for a poll on leaving the UK and uniting with Ireland.
Northern Ireland's nationalist Deputy First Minister Martin McGuinness said ahead of the vote that Britain should immediately commit to holding a vote to unite Ireland if it chose to leave the EU.
Sinn Fein chairman Declan Kearney said in a statement: "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."
In Gibraltar, the vote was overwhelmingly in favour of Britain remaining in the European Union and upon the decision Spain will seek co-sovereignty of the peninsula.
"It's a complete change of outlook that opens up new possibilities on Gibraltar not seen for a very long time. I hope the formula of co-sovereignty -- to be clear, the Spanish flag on the Rock -- is much closer than before," Spain's acting foreign minister Jose Manuel Garcia-Margallo said.
The majority of those living in Gibraltar are British citizens with British passports, although thousands of Spaniards cross from mainland Spain to work on the peninsula every day.
Newshub. / NZN / AAP