POLYAS Election Glossary

We provide explanations and background information on elections, voting rights and digital democracy

Supplementary Vote

The supplementary vote system is a form of preferential voting devised in the United Kingdom. It was originally proposed by Labour MP Dale Campbell-Savours in 1989 as an alternative to the first past the post system in UK parliamentary elections. Although it has since failed to be implemented in elections of the national parliament, it is now in use for all directly elected mayors in England, as well as for elected Police and Crime Commissioners.

How it works

  1. Voters mark only their first and second preferred candidates on a ballot paper which may contain more than two candidates.
  2. If no single candidate receives an absolute majority of first preferences, all other candidates apart from the top two on first preferences are eliminated from the race
  3. The second preferences of those eliminated ballots are then distributed to the top two candidates
  4. The candidate with the most votes at the end of this process wins the election
See also: Proportional Vote


< Go back