Britain's opposition Labour Party Leader Ed Miliband speaks at the London Business School in London. A future Labour government is unlikely to hold a referendum on Britain's membership of the European Union this decade, party leader Ed Miliband pledged. REUTERS/Suzanne Plunkett

London - A future Labour government is unlikely to hold a referendum on Britain's membership of the European Union this decade, party leader Ed Miliband said in a political gamble that lowers the chances of Britain leaving the 28-member bloc.

Seeking to define the battle lines of the 2015 election, Miliband said he wanted to fight Prime Minister David Cameron on the 'cost of living' rather than spooking businesses with the prospect of a British exit from the EU.

In sharp contrast to Cameron's promise to reach a new settlement with the EU before holding an in/out vote by the end of 2017, the 44-year-old head of the opposition Labour party said he would only hold a referendum if more powers were transferred to Brussels.

Such a transfer is unlikely at this stage, particularly since future European political and economic integration would probably come within the euro zone, of which Britain is not a member.

“I am announcing that the next Labour government will legislate for a new lock,” Miliband said in a speech to the London Business School. “A lock that guarantees that there will be no transfer of powers without an in/out referendum.”

“I believe it is unlikely this lock will be used in the next Parliament,” Miliband said on Wednesday.

By offering only a distant and conditional referendum, Miliband is seeking to turn Cameron's EU strategy against the ruling Conservatives: he is betting that Europe is much less of an issue than the economy for most British voters.

Miliband said Cameron's Conservative party had an “all consuming and damaging obsession” with Europe that had sent a chill down the spine of investors.

“We know where the centre of gravity in the Conservative Party now lies: Britain outside the European Union, robbed of influence and power,” said Miliband.

Cameron, who is under pressure from eurosceptics in his Conservative party and the anti-EU UK Independence Party, says Britain can reshape its EU ties and that Labour is afraid of giving British voters a say on Europe.

“Only the Conservative Party can guarantee and deliver that in/out referendum,” said Cameron, whose Liberal Democrat coalition partners have, like Labour, promised such a vote only if more powers are passed to Brussels.

The Labour leader is gambling that Conservative focus and divisions over Europe will turn voters off Cameron in 2015 and that Labour's referendum pledge will please business which has criticised Labour for its tax and energy policies.

The Confederation of British Industry, a powerful business lobby, welcomed Miliband's speech, saying it supported Miliband's view that Britain should seek to reform the EU from the inside.

Underlining corporate concerns about the economic impact of a British exit, billionaire financier George Soros suggested on Wednesday it might cost jobs and investment.

“I leave it to the British business community, particularly the multi-nationals that set up factories here as an entry point into the common market, to explain to the British public what they stand to lose, in one word - jobs,” Soros told journalists in London.

Miliband used the waving of Europe's blue-and-golden-starred-flag by some Ukrainian protesters in Kiev to argue that voters should not forget the European Union symbolised peace and prosperity for many after centuries of European strife.

But the Labour leader also cautioned that the EU's reputation was at a low ebb: he said EU leaders should do more to build a stronger economy and address voter anxiety over immigration.

“Britain's future lies in the European Union,” Miliband said. But he added: “We need to show we can act on people's concerns about immigration ... Under Labour, Britain will not be part of an inexorable drive to an ever closer union.”

Opinion polls show about 40 percent of British voters want to stay in the EU while about the same proportion want to leave, though polls also show widespread hostility to immigration and dissatisfaction with established political parties.

Europe was the undoing of the last two Conservative prime ministers, John Major and Margaret Thatcher, but polls show that the economy, immigration, health and welfare trump Europe as an issue for voters.

“People do not regard Europe as a major topic in their lives,” said Peter Kellner, president of the YouGov pollster.

“The importance of this is, does it add to or subtract from Ed Miliband's reputation as a potential prime minister? His big problem isn't policy as such: it is that people don't think he is up to the job of being prime minister.”