By William James and Joshua Franklin
LONDON (Reuters) - Prime Minister David Cameron's Conservatives could lose the next election if they continue to argue about Britain's membership of the European Union, the party's last premier warned on Tuesday.
John Major, whose stint as prime minister between 1990 and 1997 was dogged by party revolts over Europe, said Cameron risked exposing long-standing divisions and turning off voters by conceding ground to hard-core Conservative Eurosceptics.
"People simply do not vote for parties that cannot agree among themselves," Major said at a parliamentary lunch, making a rare return to the British political arena he has largely avoided since a heavy election defeat 16 years ago.
Earlier this year, in an attempt to defuse a revolt from members on the right of his party, Cameron decided to back legislation to enshrine a promise of a 2017 referendum on European Union membership in law.
Major said he did not support the bid for a legal guarantee on the referendum because it highlighted the party's disparate views, but he backed holding a vote in 2017 as a way to end to a "dreary and ancient argument" over Britain's EU membership.
"I think he's right to have a referendum because this issue has bedevilled and poisoned British politics for the best part of the last 25 years," Major said, adding that he expected Labour to eventually match that promise.
"Will it totally end the argument? Probably not. Will it turn it to the fringes of politics? I think it probably will. It'll no longer be a mainstream item and that's going to be attractive."
Major called on Britons to vote in favour of remaining a member of the 28-country EU in any referendum.
"It would be folly beyond belief, in a world of 7 billion people who are binding more closely together, for brave little 'Blighty' to decide she's suddenly going to ... cut off Europe in a thick fog and decide to go on her own," Major said.
He backed a drive by Cameron to renegotiate Britain's relationship with Europe and said leaving the bloc would cut off access to Europe's single market and leave exporters forced to comply with EU regulations they no longer had control of.
"We need to support the prime minister and the government in their renegotiations. I think Mr Cameron's negotiating hand is a good deal stronger than many people imagine and I've done a fair bit of negotiating in Europe," Major said.
Major said that the best way to tackle the rise of the anti-EU UK Independence Party (UKIP) was to argue that voting UKIP would split the Conservative vote and hand power to an opposition Labour party more open to the European Union.
A YouGov poll for The Sun newspaper on Monday put UKIP, once dismissed by Cameron as "fruitcakes, loonies and closet racists", on around 13 percent of the vote behind the Conservatives on 33 percent and Labour on 38 percent.
(Editing by Robin Pomeroy)