BrexitReuters File

The campaign for Britain to leave the EU has been backed by 250 business leaders, including a former chief executive of HSBC, the Vote Leave group said Saturday, hoping to counter the view UK businesses back staying in the bloc.

The camps arguing for and against Britain staying in the European Union ahead of a June 23 referendum on British membership have both made the economic impact of a "Brexit" a cornerstone of their campaigns.

Last month, the bosses at more than a third of Britain's biggest companies, including major oil companies Shell RDSA.L and BP, and its largest telecoms group BT, said leaving the EU would put jobs and investment at risk.

Vote Leave, one of the groups supporting a British exit, unveiled Saturday its own list of backers, including Michael Geoghegan, former chief executive of HSBC Group and Tim Martin, the boss of pubs group JD Wetherspoon.

"With our growing list of business supporters, Vote Leave will make that case that whilst the EU might be good for big multinationals, for smaller businesses it acts as a job destruction regulatory machine," Matthew Elliott, chief executive of Vote Leave, said.

However, the Sunday Times newspaper reported two of the well-known names on the list — John Caudwell, founder of Phones4U, and David Ross, the co-founder of Carphone Warehouse — had not signed up.

"You have to question how this list has been compiled," the paper quoted a spokesman for Caudwell as saying.

Vote Leave also said it was forming a Business Council to argue that EU membership was holding back business.

That group will be headed by John Longworth, who quit as director general of the British Chambers of Commerce (BCC) lobbying group after he spoke out in favour of leaving the EU, accusing Prime Minister David Cameron of trying to scare voters into backing his case to stay in the bloc.

Meanwhile, the Times newspaper reported that hedge funds were planning to use exit polls to make big profits on the day of the referendum.

Under electoral law, it is illegal to publish the results of such polls while people are still voting, but a private poll could allow traders to exploit moves in the currency market, with the sterling expected to rise sharply against the dollar on the back of an "In" vote but decline if Britons vote for an exit.

The sterling fell to multi-year lows this week on a perceived rise in the chances of an EU exit, and on companies and fund investors hedging against it, though the currency later steadied.

"There is a lot of interest around Brexit, particularly from the big U.S. funds," one unnamed broker told the Times.

The odds of a Brexit narrowed Tuesday as the Brussels bombings were seen boosting the "Out" campaign.