LONDON, United Kingdom (AFP) — Foreign currency dealerships have seen a boom in trade in recent days with Britons lining up to sell their pounds, concerned about a devaluation if Britain votes to leave the EU on Thursday.

“People are purchasing to be on the safe side,” said Niroshan Fernando, senior manager at the Thomas Exchange Global foreign currency business on Cannon Street in the City of London financial hub.

“We’ve seen about 60 to 70 percent more in the last couple of days in terms of volume,” he said.

“It’s all due to panic buying. I think we’ll see similar queues tomorrow because people are still unsure, even if we vote to Remain,” he added.

One City worker in his 40s queuing outside the shop said he was going on a foreign holiday in two weeks’ time but was changing some money early just in case.

“I’m trying to hedge a bit, so I’m getting some of it now and some of it later,” he said.

Analysts have said the pound could fall by between 15 percent to 20 percent if Britain votes to leave although the currency surged against the euro and dollar to 2016 highs on Thursday on the back of expectation of a “Remain” victory.

Billionaire George Soros, who famously profited by betting against the pound in a 1992 currency crisis, earlier this week predicted a “Black Friday” for Britain the day after the vote if it votes “Leave”.

“The value of the pound would decline precipitously,” the 85-year-old wrote in the Guardian newspaper.

Rasaka Dissanayake, business development manager at online and bricks-and-mortar trader BestForeignExchange.com, said customers had been queueing up to 40 minutes at their shops this week.

“Most people wanted to buy their foreign money before the referendum,” he said — mainly relatively small amounts in the hundreds or thousands of pounds.

“It is mostly to exchange sterling against dollars and euros, but other holiday destination currency as well, like the ones from Croatia and Czech Republic,” he said.

Post Office Travel Money, which accounts for a quarter of all British foreign exchange transactions, said it had seen a spike in deals.

It reported a 113-percent jump in sales of pounds to buy euros and dollars on Wednesday alone — compared to the same day a year ago.

Since the beginning of June, the increase was 41 percent compared to the same period last year, said the operator, which is present in Britain’s more than 10,000 post office branches.

Travelex, another foreign currency trader, also said there had been a 101-percent increase in online deals on Wednesday, compared to Wednesday last week.

“It’s highly possible that this surge is due to the uncertainty being fuelled by today’s vote,” said David Swann, head of pricing for UK, Europe and the US for Travelex.