According to the Electoral Reform Society 74 countries around the world use proportional representation, and the world has changed a lot since the AV referendum in 2011. If a referendum returns a vote in favour of PR, it could be tested on an experimental or temporary basis.
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The first-past-the-post system has led to what many people believe to be a 'Uni-Party' choice, offering no real choice at all. We believe it is a democratic right to be able to vote for a genuinely diverse range of options, in the understanding that your vote will actually make a difference.