By Peter Griffiths
LONDON (Reuters) - Eight out of 10 British manufacturers would choose to stay in the European Union if a referendum on membership of the 28-nation bloc were held today, a survey found on Monday.
The results feed into a debate over Britain's future in Europe that could help decide if Prime Minister David Cameron wins a second term in office at the next election in 2015.
Cameron has promised to try to renegotiate Britain's EU ties and hold an "in/out" referendum by the end of 2017, a move seen as an attempt to placate Eurosceptic rebels in his Conservative Party and to counter the UK Independence Party, whose call to leave the EU has lured voters away from the Conservatives.
The poll, for the EEF, the manufacturing sector's biggest trade body, also found that three-fifths of companies thought Britain should try to reform Europe as a whole rather than seek special treatment for itself.
EEF Chief Executive Terry Scuoler said the results suggested manufacturers wanted to stay in a reformed EU and feared the economic fallout of leaving.
"Britain must not gamble on its future in Europe. The stakes are enormous," he said. "It is naive to think we can pull up the drawbridge and carry on as normal. Billions of pounds of trading opportunities are at stake."
Nearly half of Britain's exports go to the EU, its biggest trading partner and a single market of 500 million people.
The poll of more than 200 manufacturers found 85 percent would choose to stay in the EU, if given a say in a referendum.
A majority also supported Cameron's campaign to reduce EU regulation, but said it would probably not do much to boost growth. A government report into reducing EU regulation is due to be published in the coming days.
A separate survey for the Mail on Sunday newspaper found 46 percent of voters would choose to leave if a referendum were brought forward to next year, 38 percent would opt to stay in, and 16 percent were undecided. Some anti-EU Conservatives want an early EU referendum.
The results were reversed when people were asked how they would vote if Cameron were to win concessions from the EU, with 47 percent wanting to stay in and 30 percent wanting to leave.
Eurosceptics see the EU as an interfering and expensive bureaucracy imposing excessive regulation and posing a threat to British sovereignty.
The poll comes a week after Cameron's pro-EU deputy, Nick Clegg, who shares power in a two-party coalition government, urged businesses to make the case for staying in the bloc. He said it would be "economic suicide" to leave.
However, anti-EU groups accused him of scaremongering. They say Britain could prosper outside the bloc as a more flexible economy, free to sign new trade deals.
(Editing by Alison Williams)