Top European firms warn on Brexit

The leaders of 50 of Europe's mightiest companies, from Shell and BP to Heineken and BMW, warned Tuesday that Britain will be weaker if its people vote to break away from the European Union.

Weeks away from the June 23 referendum in Britain, the corporate chiefs said the continent, already challenged by terrorism and migration, now faced a new "fork in the road".

"An unravelling of the single market and the rules governing 28 countries would reduce, not boost our prosperity," the members of the European Round Table of Industrialists said in a joint statement.

A united Europe benefits investment and job creation, they said.

"While respecting the decision of the people in the United Kingdom, we believe that a Europe without the UK would be weaker, just as the UK itself would be weaker outside Europe."

The Europe Union is the world's largest economy, accounting for 16 percent of world trade, which gives it "tremendous bargaining power" in striking trade deals, the company chiefs said.

Over the past 60 years, people and companies had benefited from greater wealth, security and quality of life because of the stronger ties between member states, they said.

The European Union must be improved, however the business chiefs said, stressing an urgent need to cooperate across borders on security against terrorism and to address the refugee crisis.

They pressed, too, for an integrated EU energy market, better education and skills training and the development of digital technology and innovation across the bloc.