Supplementary Vote

• Where is SV used?

  London mayors (and other elected mayors)
• How does SV work?

  Each voter is allowed a first and second preference vote. Any candidate who received more than 50 % of the first preference vote is selected automatically. If this doesn’t occur, all candidates except the top two are eliminated and the second preference votes for the two candidates are added to produce an overall winner
• Advantage 1: It ensures broad support for the winner


  Sadiq Khan, for example, has the largest personal mandate of any elected politician in British history
• Advantage 2: simple and straightforward to use
• Advantage 3: Greater choice than FPTP

  Voters can indicate a second preference and choose their desired candidate whilst also choosing between the two candidates most likely to win
• Disadvantage 1: winner doesn’t need to get an absolute majority of the votes cast
• Disadvantage 2: To have influence over the outcome, voters need to be able to identify the likely top two candidates which isn’t always clear, with he exception of London
• Disadvantage 3: The least unpopular candidates are more likely to win, rather than the most popular
• Disadvantage 4: If SV was used for constituencies in UK Parliament elections, the problem would still remain of votes for candidates that don’t win being wasted, though to a lesser extent than FPTP