Lib Dem proposal is passed by 137 votes to 135 with some Labour backbench support but is unlikely to become lawUK politics live – latest updatesMPs have voted narrowly in favour of introducing a proportional representation electoral system, in a move that will almost certainly not change the law but is nonetheless a symbolically significant moment for UK politics.The vote on a Liberal Democrat bill calling for a PR system for UK parliamentary elections and for local elections in England was passed by 137 votes to 135. It is believed to be the first time the Westminster parliament has backed