Prime Minister Andy Burnham has committed Labour to fighting the next general election with a manifesto pledge to change the UK's electoral system.
Burnham made the commitment during his speech to the Labour Party Conference in Liverpool, where he also announced the creation of a new National Commission on Electoral Reform.
The move means Labour is now formally committed to going into the next election promising a change to the way MPs are elected, although the precise replacement for the current First Past the Post system has not yet been decided.
Labour will put voting reform in its manifesto
Burnham told the conference that Labour would contest the next election with a manifesto commitment to change the electoral system so that every vote counts towards the composition of Parliament.
The Prime Minister said Britain's political system needed to respond to increasing fragmentation in the electorate and argued that the existing arrangements risk governments taking office with relatively small shares of the national vote.
Labour members have previously backed electoral reform at party conference, and Burnham said he agreed with those calls.
National commission to examine replacement system
The new National Commission on Electoral Reform will examine possible changes to the voting system and is expected to report before the next general election.
Burnham has invited other political parties to participate in its work. Labour says community organisations, trade unions, businesses, faith groups and voters from across the political spectrum will also be invited to contribute.
The commission's work is intended to inform the detailed reform Labour eventually places before voters.
Replacement voting system has not been decided
Despite the manifesto commitment, Labour has not yet announced which electoral system would replace First Past the Post.
Burnham has previously supported proportional representation, but the creation of the commission means the detailed model remains to be determined.
It would therefore be premature to state that Labour has committed to a particular form of proportional representation. What has been explicitly confirmed is a commitment to change the electoral system, with the commission tasked with helping shape what comes next.
Potentially major change to Westminster elections
Members of the House of Commons are currently elected using First Past the Post, under which the candidate receiving the most votes in each constituency wins the seat.
A move away from that system would represent one of the most significant changes to Westminster elections in generations.
Burnham argued that the political landscape has changed as support has become increasingly divided among several parties and said reform was needed to ensure voters' choices were better reflected in Parliament.
The Government has not announced legislation to implement a replacement system during the current Parliament. The immediate commitment is for the commission to conduct its work before Labour goes into the next general election promising electoral change.