Banks across Europe have installed bunk beds and sleeping bags in their offices so their staff can cash in on the result of today's historic referendum.

With the last polls suggesting the EU referendum is too close to call, banks have commissioned private exit polls so they can profit from placing big bets on the outcome before the result is officially announced in the early hours of tomorrow morning.

Takeaway pizza, sushi and infinite amounts of coffee will be on hand for bankers working through the night in the City, while special 'war rooms' will be available for emergency meetings and 'dealing rooms'.

Regulators have instructed banks to fill their cash machines full of money to avoid the kind of queues that could trigger a similar run on the banks as Northern Rock witnessed in 2007.

Banks across Europe have installed bunk beds and sleeping bags in their offices so their staff can cash in on the result of today's historic referendum. With the last polls suggesting the EU referendum is too close to call, banks have commissioned private exit polls so they can profit from placing big bets on the outcome before the result is officially announced in the early hours of tomorrow morning

They have also told consumer banks not to conduct any IT upgrades that could crash payment systems and trigger fears that banks are not holding enough cash.

Barclays are among the banks bringing in sleeping bags, while American investment bank JPMorgan has booked hotel rooms for its employers near to its offices in Canary Wharf.

Senior bankers at Citigroup, Goldman Sachs and Morgan Stanley are being asked to stay overnight - in particular traders in foreign exchange and interest rate markets where the biggest profits are at stake.

Tonight there will be no official exit poll - which is seen as the most accurate of all polls because it asks voters how they have voted rather than how they will vote - because broadcasters decided against commissioning one because they have no way of knowing how accurate it would be.

Instead the only exit polls will be private surveys conducted at significant expense by hedge funds and investment banks.

It will allow them to trade based on results no one else knows before the result is announced and they will hope to make millions in profit before the markets open at 8am on Friday morning.

Billionaire George Soros (pictured), who famously made millions by betting against the pound before it crashed, warned earlier this week that a Brexit vote could produce a 'Black Friday' as markets react in horror to instability caused by the result

In preparation for volatility in the markets, some banks are switching off their algorithmic trading systems, according to the Guardian.

Computerised trading dominates City dealing rooms as it allows banks to buy and sell much faster than the human touch but some banks fear that volatility caused by the uncertainty of the referendum could mean computers buying or selling too quickly.

It means their investors can only conduct trading through verbal orders instead of through computers.

Other banks are putting plans in place for algorithmic trading systems to be overridden by humans at short notice in the event of high volatility.

The final polls suggested the result of the referendum is still too close to call.

An average of the last six polls by Professor John Curtice, who was the only pollster to correctly predict the outcome of last year's General Election, suggests a four-point win for Remain.

An exclusive survey for the Daily Mail and ITV News, gave the Remain camp a lead of six points, by 48 per cent to 42 per cent – but 11 per cent of electors said they were still undecided.

The In camp are ahead of Leave by 52 per cent to 48 per cent, according to an Ipsos Mori survey for the Evening Standard this afternoon. To add further uncertainty to the outcome, 12 per cent of those polled said they could switch sides as they head for the polling booth.

But according to an online poll by Populus the Remain campaign is at 55 per cent compared to Leave on 45 per cent.

Banks are bracing themselves for the worst volatility since the Black Wednesday crash in 1992 after sterling crashed out of the European Exchange Rate Mechanism.

Billionaire George Soros, who famously made millions by betting against the pound before it crashed, warned earlier this week that a Brexit vote could produce a 'Black Friday' as markets react in horror to instability caused by the result.

The final few polls of the referendum campaign suggested the result will go down to the wire, with a YouGov survey giving a Remain a two-point lead and polls by TNS and Opinium showing the reverse

He claimed the collapse in the value of the pound on Friday could be even bigger if Britain votes for Brexit and he warned it would leave people poorer.

Currency and stock markets have been on a roller-coaster ride during the referendum campaigning, plunging over the past fortnight as a succession of polls showed a Brexit lead.

But as market hopes of a Remain vote were raised this week - after a week of jitters following several polls showing a Brexit lead - the pound hit fresh highs against the dollar.

Sterling has continued its recent revival, after weeks on the slide amid fears over polls showing a strengthening Leave vote, rising 0.4 per cent to $1.49 and cementing a 6 per cent rise since this time last week.

Against the euro the pound has stayed in the region €1.30, up from €1.26 a week ago.

But in a sign of the possible chaos that could ensure to come once votes have been counted, City banks - including UBS, HSBC, Morgan Stanley and Bank of America Merrill Lynch - have written to clients telling them to prepare for disruption once the EU referendum result is declared.