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Supplementary vote system

At a Combined authority or Combined county authority mayoral election, if there are only two candidates, the mayor is elected under the first past the post voting system.1

If there are three or more candidates, the mayor is elected using the supplementary vote system where voters can cast a first and second preference vote for mayor.2

First count

At the first count, only the first preference votes are counted. The processes for sorting and counting votes for a single member vacancy should be followed.

If a candidate obtains more than 50% of the first preference votes, they are declared elected. If no candidate obtains more than 50% of the first preference votes, the top two candidates (or more if there is a tie) remain in the contest while the rest are eliminated. You must inform the CARO/CCARO of your local totals.3

The CARO/CCARO will then collate the first preference vote totals for the whole of the combined authority or combined county authority area. If a candidate obtains more than 50% of the total number of valid first preference votes across the whole of the combined authority or combined county authority area, they will be declared elected by the CARO/CCARO.4

If no candidate obtains more than 50% of the total number of valid first preference votes across the whole of the combined authority or combined county authority area, the top two candidates (or more if there is a tie) remain in the contest while the rest are eliminated. The CARO/CCARO will inform you whether a second count is needed. 

You will not be able to ascertain with certainty which candidates will remain in the contest until the CARO/CCARO has calculated the totals for the whole of the combined authority area. 

Your area may have strong support for a candidate that is then eliminated once all the local totals have been collated. This should be kept in mind when taking any actions in preparation for the second count. 

Second count

You will need to sort the ballot papers into: 

  • ballot papers on which a first preference vote was given to one of the candidates remaining in the contest – these are not counted again at the second count 
  • all other ballot papers containing a valid first preference vote sorted by:
    • those containing a second preference vote for one of the continuing candidates, sorted by candidate 
    • those containing a second preference vote for a candidate who is not continuing in the contest (these do not form part of the second count, but the total number of ballot papers should be counted for audit purposes and packaged separately)
    • those ballot papers requiring adjudication

All ballot papers containing valid second preference votes for the continuing candidates are counted, and the total number added to the number of first preference votes each of those candidates received. The candidate with the highest total number of votes across the combined authority or combined county authority area is declared elected.  

At the end of the second count you must inform the CARO/CCARO of your local totals. 

The CARO/CCARO will then collate the second preference vote totals for the whole of the combined authority or combined county authority area, and add these to the total number of first preference votes each of those candidates received. 

The candidate with the highest total number of votes will be declared elected, and the CARO/CCARO will inform you of the result.

Last updated: 19 June 2026