LONDON (Reuters) - Britain's opposition Labour party voted on Saturday to change its century-old relationship with trade unions to try to revitalise the party before next year's parliamentary election.
The left-leaning party voted overwhelmingly at a special party conference to reform its link with the unions, with 86 per cent in favour of adopting a one-member, one-vote system in leadership elections.
In such elections the vote of an ordinary party member will now have the same weight as that of a member of parliament, and union members will vote as individuals rather than in a bloc.
Previously leadership contests were decided by a complex electoral college system with members having a third of the vote, MPs a third, and unions controlling the final third.
The shift also ends automatic enrolment of union members in the Labour party. They will now have to choose to opt in when joining unions, which are the party's biggest source of funding.
The change was proposed last year when Labour tried to limit the damage from a row over outside influence in the party.
Britain's biggest union, Unite, was accused - but later cleared - of hijacking the selection of a candidate to contest a parliamentary seat in the Scottish town of Falkirk to increase its influence in government.
Labour leader Ed Miliband said the changes would attract thousands of new supporters before Britain's election in 2015.
"I did not believe we could face up to the challenges the country faced if we didn't face up to the challenges faced by our party," he told the conference.
He later tweeted: "The reason we have changed our party today is so that we never lose touch again ... Now the battle to change our party is over. The fight for the future of Britain has just begun."
But Grant Shapps, chairman of the Conservative party which leads the coalition government, dismissed the changes as "a big victory for the unions".
"Ed Miliband is left with a situation where the unions are now his political life-support machine," he told the BBC.
Labour is leading in opinion polls for the national election with 38 percent support, compared with 33 percent for the Conservatives. The coalition government's junior partner, the Liberal Democrats, have 10 percent backing.
Reporting by Belinda Goldsmith; Editing by Alistair Lyon