Other currencies across Asia suffered badly on worries that alarmed investors could pull funds out of emerging markets. Photograph: (Getty)
The pound sinks a staggering 9 per cent, fall is even larger than during the global financial crisis
Carnage came to world markets on Friday as early voting returns suggested Britain was on the brink of leaving the European Union, threatening the existence of the entire bloc and its single currency.
Risk assets were scorched as investors fled to the safety of top-rated government debt, with FTSE futures off 6 per cent and EMINI S&P 500 futures down 3.5 per cent.
The British pound had collapsed no less than 15 US cents, easily the biggest fall in living memory, while the euro slid 2.8 per cent as investors feared for its very future.
Sterling sank a staggering 9 per cent to $1.3550, having carved out a range of $1.3462 to $1.5022. The fall was even larger than during the global financial crisis and the currency was moving two or three cents in the blink of an eye.
"Sterling is getting smackadoodled," said Tim Kelleher, Head of FX Institutional Sales New Zealand for ASB Bank in Auckland. "While we thought it was all going to be "Remain", it's quite clearly not going to be as clear cut as that."
Early official results showed the margins were nail-bitingly tight but pointing to a "Leave". Betting firm BetFair estimated the probability of leaving as high as 74 per cent.
Traders were particularly spooked by returns from Sunderland showing a large majority for the "Leave" camp and just a narrow win for "Remain" in Newcastle.
With half of 382 counting areas declared, the Leave camp was put at 51.3 per cent against 48.7 per cent for "Remain", according to Reuters calculations.
The tremors shook all asset classes and regions.
The safe-haven yen sprang higher to stand at 101.00 per dollar, having been as low as 106.81 at one stage.
That dragged the Nikkei down 3 per cent and prompted warnings from Japanese officials that excessive forex moves were undesirable. Indeed, traders were wary in case global central banks chose to step in to calm the volatility.
Other currencies across Asia suffered badly on worries that alarmed investors could pull funds out of emerging markets.
MSCI's broadest index of Asia-Pacific shares outside Japan slid 3.3 per cent, its biggest fall in 10 months, while Shanghai stocks lost 1 per cent.
UK bank shares listed in Hong Kong tumbled on the prospect of a destabilising exit. HSBC fell 8 per cent while Standard Chartered sank 9 per cent.
Financial markets have been racked for months by worries about what Brexit, or a British exit from the European Union, would mean for Europe's stability.
Early opinion polls had favoured the "Remain" camp and perhaps led to a false sense of complacency in markets. An Ipsos MORI poll put the lead at 8 points while a YouGov poll out just after polls closed found 52 per cent of respondents said they voted to remain in the EU while 48 per cent voted to leave.
Sovereign bonds came back into favour as safe harbours against market volatility, with U.S. 10-year Treasury futures jumping 1.29 points.
Yields on the cash note fell 16 basis points to 1.58 per cent, the steepest one day drop since 2011.
Investors also priced in even less chance of another hike in U.S. interest rates given the Federal Reserve had cited a British exit from the EU as one reason to be cautious on tightening.
"It adds weight to the camp that the Fed would be on hold. A July (hike) is definitely off the table," Mike Baele, managing director with the private client reserve group at U.S. Bank in Portland, Oregon.
Commodities likewise swung lower as a Brexit would be seen as a major threat to global growth. U.S. crude shed $2.02 to $48.09 a barrel in erratic trade while Brent fell $1.91 to $49.00.
Copper slipped but gold galloped more than 3 per cent higher thanks to its perceived safe haven status.