LONDON (AFP) - Britain's EU referendum has prompted a global outpouring of warnings in recent months about the potential consequences of a Brexit, ranging from the gloomy to the downright apocalyptic.
European Council President Donald Tusk gave perhaps the most dramatic of any warning from a global leader, suggesting last week that this could be the end of the West as we know it.
"As a historian, I am afraid this could in fact be the start of the process of the destruction of not only the EU but also of Western political civilisation," he told Germany's Bild newspaper.
The British pound took a wild ride on the markets as results began coming in Friday morning Singapore time, with a series of victories for the anti-EU camp fuelling a slump in the currency hours after it touched a 2016 high of US$1.50.
US billionaire George Soros, who famously profited by betting against the pound in a 1992 currency crisis, predicted a "Black Friday" if Britain votes to leave.
"If Britain leaves the EU it will have at least one very clear and immediate effect that will touch every household: the value of the pound would decline precipitously," he wrote in the Guardian on Monday.
Prime Minister David Cameron took a huge gamble in calling the referendum in 2013. As the results began trickling in Thursday night, 83 lawmakers from his Conservative Party released a letter urging him to stay in his post regardless of the outcome.
But there is a widespread belief that after leading the campaign to stay in the EU, Mr Cameron would have no choice but to quit if he lost.
Conservative former finance minister Ken Clarke put it bluntly: "The prime minister wouldn't last 30 seconds if he lost the referendum."
"A UK vote to exit the European Union could have significant economic repercussions," US Federal Reserve Chair Janet Yellen said this week. "It would usher in a period of uncertainty that is very hard to predict," she added, warning of volatility in global markets.
The International Monetary Fund issued a similarly downbeat assessment, warning that Brexit could deal the British economy a "negative and substantial" blow, possibly sinking back into a recession.
The Washington-based lender also warned that "contagion effects" from the decision could hit markets worldwide.
In a report released last month, the British Treasury offered two potential scenarios, neither of them cheerful: either a 3.6 per cent or 6 per cent drop in GDP two years after a Brexit.
Mr Roberto Azevedo, head of the World Trade Organisation (WTO), warned that re-negotiating Britain's trade deals would prove a huge headache following a Brexit.
British exporters would risk an extra £5.6 billion (S$10.35 billion) of annual customs duties, he said this month - and it would also need to renegotiate the terms of its WTO membership.
"Key aspects of the EU's terms of trade could not simply be cut and pasted for the UK," Mr Azevedo said. "Negotiations merely to adjust members' existing terms have often taken several years to complete - in certain cases up to 10 years, or more."
European Commission chief Jean-Claude Juncker warned on the eve of the vote that there would be no turning back if Britain decided to quit the EU.
"Out is out," he said firmly.