With five Oscar nominations, including Best Picture and Best Director, The Big Short is set to draw a crowd when it hits UK cinemas on Friday, January 22.

The critically acclaimed film – an adaptation of Michael Lewis’s excellent book of the same name – stars Christian Bale, Steve Carell, Ryan Gosling and Brad Pitt.

It tells the true story of various people in America who predicted the financial crash of 2007-08 and made huge amounts of money as a result.

But many viewers may be unaware of the small but crucial part played in those real life events by a Wetherspoon pub in Exmouth – or, more precisely, its free wi-fi.

Among those who realised before most experts that the ticking time bomb of subprime mortgages threatened to bring down some of the biggest US banks, sending shock waves through the global economy, were the founders of Cornwall Capital.

Predicting that the giant bundles of dodgy loans held by Bear Stearns would turn bad, the inexperienced hedge fund managers bought up lots of obscure insurance policies known as credit default swaps – effectively a massive bet against the banks.

As panic began to sweep the banks when they finally woke up to the looming crisis, Cornwall Capital suddenly had to sell these policies in a hurry, as Lewis explains: “One thing was clear: Their long-shot bet was no longer a long shot.

“Their Wall Street dealers had always told them that they’d never be able to get out of these obscure credit default swaps, but the market was panicking, and seemed eager to buy insurance on anything related to subprime mortgage bonds.

“The calculation had changed: For the first time, Cornwall stood to lose quite a bit of money if something happened that caused the market to rebound – if, say, the US government stepped in and guaranteed all the subprime mortgages. And of course if Bear Stearns went down, they’d lose it all.”

The only person at the firm with the know-how to complete the trades was Ben Hockett – a retired banker who becomes the character Ben Rickert in the film, played by Brad Pitt.

Unfortunately, at the critical time in August 2007 he was on holiday in Devon with his wife’s family.

“And so it was,” writes Lewis, “that Ben Hockett found himself sitting in a pub called The Powder Monkey, in the city of Exmouth, in the county of Devon, England, seeking a buyer of $205 million in credit default swaps on the double-A tranches of mezzanine subprime CDOs.

“The Powder Monkey had the town’s lone reliable wireless internet connection, and none of the enthusiastic British drinkers seemed to mind, or even notice, the American in the corner table bashing on his Bloomberg machine and talking into his cell phone from two in the afternoon until eleven at night.”

Hockett spent four days at the pub negotiating with increasingly frantic buyers at Citigroup, Merrill Lynch, Lehman Brothers and UBS in New York.

“We had positions that were being valued by Bear Stearns at six hundred grand that went to six million the next day,” recalled one of his colleagues.

By 11pm on Thursday, August 9, he was finished – becoming probably the only person to have made millions of dollars using the wi-fi at the popular town centre pub.

“Cornwall Capital, started four and a half years earlier with $110,000, had just netted, from a million-dollar bet, more than $80 million,” writes Lewis.

“They had not been the chumps at the table. The long shot had paid 80:1. And no one at The Powder Monkey ever asked Ben what he was up to.”