Scotland is highly likely to hold a second independence referendum, Scottish First Minister Nicola Sturgeon said on Friday, adding she would do what was necessary to secure the country's place in the European Union after Britain voted to leave the bloc.
"It is a statement of the obvious that the option of a second referendum must be on the table and it is on the table," she told reporters.
"I think an independence referendum is now highly likely," she added.
Scotland, which held its previous independence referendum in 2014, voted by a margin of 62 per cent to 38 per cent to remain in the EU in Thursday's referendum, putting it at odds with Britain as a whole, which voted 52 to 48 per cent in favor of Leave.
Sturgeon added: "I want to make it absolutely clear today that I intend to take all possible steps and explore all options to give effect to how people in Scotland voted, in other words to secure our continuing place in the EU and in the single market."
Northern Ireland, which is part of the United Kingdom, is now faced with the prospect of customs barriers for trade with EU-member the Republic of Ireland. Irish republicans Sinn Fein called for a vote on Irish unity following the referendum.
Leaders of Europe, born out of a determination to forge lasting peace from the carnage of two world wars, will open a two-day summit on Tuesday to grapple with the British decision.
Cameron announces he will step down
Prime Minister David Cameron announced Friday he will resign after Britons voted to leave the European Union despite his campaign to keep it in the bloc.
Cameron promised to try to "steady the ship" over the next months and did not give a precise timetable for his departure but said a new leader should be installed by early October.
"I do not think it would be right for me to try to be the captain that steers our country to its next destination," the British leader said outside his Downing Street residence in London.
He said his successor should trigger the formal process for Britain to leave the European Union.
Source: AFP
"I think it's right that this new prime minister takes the decision about when to trigger Article 50," Cameron said.
"I would also reassure Brits living in European countries and European citizens living here that there will be no immediate changes in your circumstances," he said.
Flanked by his wife Samantha, Cameron said he had fought to retain Britain's membership of the EU "head, heart and soul - I held nothing back".
But he added: "The British people have made a very clear decision to take a different path and as such, I think the country requires fresh leadership to take it in this direction".
Markets react with panic after Brexit vote
Britain has voted to break out of the European Union, striking a thunderous blow against the bloc and spreading panic through world markets Friday as sterling collapsed to a 31-year low.
Investors scrambled to sell the pound, oil and stocks as Britain took a lurch into the unknown, becoming the first country to quit in the EU's 60-year history, a culmination of decades of suspicion over European aims of creating an ever-closer political union.
Voters decided 51.9 per cent to 48.1 per cent in favour of quitting the bloc.
The BBC reported 17.4 million people voted to leave the EU and 16.1 million voted to remain.
"Let June 23 go down in our history as our independence day," said top anti-EU campaigner Nigel Farage, leader of the UK Independence Party, who had promised Britons the chance to retake power from Brussels and rein in high immigration.
"If the predictions now are right, this will be a victory for real people, a victory for ordinary people, a victory for decent people," he told supporters.
A joyous crowd chanted back to him: "Out! Out! Out!"
At the rival "Remain" party in London, subdued supporters stood glued to TV screens clutching beers -- some with their hands over their mouths.
'Eurosceptic genie'
Sterling plunged more than nine percent to $1.33, a 31-year low. World oil prices skidded by more than six percent and Asian stocks sank.
Britons appeared to have to shrugged off dire warnings that quitting the 28-nation alliance would create a budget hole requiring spending cuts and tax increases once they lose unfettered trade access to the EU.
Their decision will undoubtedly reawaken fears of a domino-effect ripple of exit votes in EU-sceptic members that could imperil the integrity of the bloc, already struggling with twin economic and refugee crises.
"The eurosceptic genie is out of the bottle and it will now not be put back," Farage said.
Dutch far-right MP Geert Wilders and French National Front leader Marine Le Pen immediately called for a referendums on EU membership in their own countries.
Prime Minister David Cameron, who led the ultimately doomed struggle to sway voters in favour of sticking with Brussels, will face immediate pressure to resign.
The bookmakers' favourite to replace him is former London mayor Boris Johnson, a rival from within his ruling Conservative Party who was the "Leave" camp figurehead.
Going it alone
The result means the world's fifth-largest economy must now go it alone in the global economy, launching lengthy exit negotiations with the bloc and brokering new deals with all the countries it now trades with under the EU's umbrella.
European Commission chief Jean-Claude Juncker has warned the EU will "not be bending over backwards" to help Britain in those negotiations. Analysts say it could take the island nation a decade to secure new trade accords worldwide.
In a worst-case scenario, the International Monetary Fund has warned that the British economy could sink into recession next year and overall economic output would be 5.6 percent lower than otherwise forecast by 2019, with unemployment rising back above six percent.
Thousands of jobs in the City could be transferred to Frankfurt or Paris, top companies have warned. The Brexit camp argued that the business world will adapt quickly, however, with Britain's flexible and dynamic economy buoyed by new economic partners and selective immigration.
Japanese Finance Minister Taro Aso told an emergency press briefing that Tokyo was "extremely worried" about the risks to the global economy and markets but stood ready to respond "firmly".
The campaign has left Britain riven in two, marked by the brutal murder of pro-"Remain" British lawmaker Jo Cox, a mother of two who was stabbed, shot and left bleeding to death on the pavement a week ahead of the vote.
WATCH: What are the implications of leaving EU?
Disintegration
German Foreign Minister Frank-Walter Steinmeier warned this month that a British departure would be a shock requiring quick action to avert the "disintegration" of the bloc.
"It looks like a sad day for #Europe +the United Kingdom," he wrote on Twitter on Friday.
Small countries that are economically at least as affluent as the UK are the main ones at risk, especially Denmark and potentially also Sweden," said Carsten Nickels of the Teneo analyst group in Brussels.
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Global markets face Brexit blood bath
Immigration and an erosion of economic security have become rallying cries for populist challenges that remain scattered across in Europe, just as they have for Donald Trump's campaign in the US presidential election.
The bloc will have to learn lessons not only from events in Britain but from the rest of Europe, Juncker said ahead of the referendum, warning against a rapid push for more integration.
"This euroscepticism is not only present in Britain," he said.
