A group of more than 100 leaders of major businesses on Tuesday backed Prime Minister David Cameron's campaign for Britain to remain in the European Union, saying a British exit, or Brexit, would "deter investment and threaten jobs."
"Business needs unrestricted access to the European market of 500 million people in order to continue to grow, invest and create jobs," the business leaders said in a letter published in the Times.
"We believe that leaving the EU would deter investment, threaten jobs and put the economy at risk," the letter read.
The nearly 200 signatories included top executives from 36 companies listed on London's FTSE 100 index.
Among the companies represented are Airbus UK, British Telecom, BP, Diageo, EasyJet, Goldman Sachs International, GSK, HSBC, Rio Tinto, Rolls Royce, Royal Dutch Shell, Ryanair, SABMiller, Siemens Manufacturing, Standard Chartered, Virgin Media and Vodafone.
"The businesses we lead represent every sector and region of the UK," they wrote. "Together we employ hundreds of thousands of people across the country."
Cameron's deal with the 27 other EU leaders last week means "Britain is better off staying in a reformed European Union," they added, highlighting agreements to reduce bureaucracy, deepen the single market and pursue international trade deals.
The Confederation of British Industry, which represents some 190,000 businesses, has also backed Cameron, praising the EU reform package as "a major step forward."
Britain will conduct a referendum on June 23 on whether or not to remain part of the EU.
Eurosceptics inside Cameron's ruling Conservative party have provided the strongest support for the "leave" campaign.