LONDON (Reuters) - A group of lawmakers from Britain's opposition Labour Party said on Wednesday they had formed an organization to campaign to quit the European Union should Prime Minister David Cameron's plan to renegotiate Britain's ties with the bloc fail.
Cameron has pledged to reshape the country's EU ties before holding an in-out EU membership referendum by the end of 2017 and the move highlighted the existence of long-standing divisions in the center-left Labour Party over Europe.
The creation of the group, Labour for Britain, also raised the prospect of Labour members of parliament joining forces with Eurosceptics from Cameron's right-leaning Conservatives, who are also split on the issue.
Labour, which suffered a crushing defeat to Cameron's party in a national election only last month, recently dropped its opposition to his pledge to hold a referendum though its official position remains staying in the EU.
But a group of Eurosceptic Labour lawmakers and the party's largest private donor said on Wednesday that unconditionally uniting behind the 'in' campaign would "significantly weaken" Britain's negotiating position.
Labour should push for more radical reforms which would be acceptable to those in the party who are critical of Britain's relationship with Brussels, said Labour for Britain founders and Labour lawmakers Kate Hoey, Graham Stringer and Kelvin Hopkins.
"Labour supporters and voters need to have their voice heard in the renegotiation process and the party shouldn't be scared to contemplate leaving the EU if it ends up being a sham," group secretary and Labour donor John Mills said.
"Labour for Britain will provide the forum for that voice and will play an important role in the national debate over the coming few years."
It was unclear how many members the new group has.
(Reporting by Kylie MacLellan; Editing by Andrew Osborn)