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Counting the votes

The day after polling day, the counting of votes cast in the 2020 elections for the Mayor of London and the London Assembly will begin.

In 2016, this process took place in three count centres across London: Alexandra Palace, Excel, and Olympia. Votes were counted electronically.

The 14 Constituency London Assembly Members are announced by the relevant Constituency Returning Officers. This takes place in the count centre.

The declaration of the 11 Londonwide Assembly Members and the Mayor of London is made by the Greater London Returning Officer. This takes place at City Hall once all of the votes are counted.

How your votes are counted: e-counting

Due to the scale and complexity of the elections in London – with three ballot papers and three different voting systems – counting of the votes is carried out electronically, known as e-counting. This process has a number of stages to ensure that all votes are counted.

Once all the votes in a contest are counted, the e-counting software calculates the results. These calculations are checked by the Constituency Returning Officer and the Greater London Returning Officer before being declared.

What are the different stages of the count?

Ballot papers are split into batches. They are then registered, scanned and verified.

Registered: where the number of ballot papers in each batch is counted and logged on the system

Scanned: the process of feeding the ballot papers from that batch through the scanning machine to read the votes

Verified: checking the number of papers scanned matches the number of ballot papers registered in that batch

How the Mayoral results are calculated

The Mayor of London is elected by the supplementary vote system.

Each voter has a first and second choice vote. If a candidate receives more than half of all the first choice votes they are elected immediately. If this does not happen, the two candidates with the most first choice votes go through to a second round. All other candidates are eliminated.

The second choice votes of everyone whose first choice has been eliminated are then counted. Any votes for the remaining two candidates are added to their first round totals.

The candidate with the highest combined total of first and second choice votes is elected as Mayor of London.

How the Constituency London Assembly Member results are calculated

The 14 Constituency London Assembly Members are elected using the first past the post system. This means the candidate in each constituency with the most votes is elected as a Constituency London Assembly Member.

How the Londonwide Assembly Member results are calculated

The 11 Londonwide Assembly Members are elected using a form of ‘proportional representation’. Votes from across London for the Londonwide Assembly Members are added together. The 11 seats are then allocated based upon a mathematical formula – the Modified d’Hondt Formula. This takes into account the total votes cast in the Londonwide ballot together with the number of Constituency London Assembly Member seats that each political party has already won.

11 rounds of calculations take place to fill the 11 vacant Assembly Member seats, with the party or independent candidate with the highest result at each round being allocated the seat. Seats won by parties are allocated to party candidates in the order they appeared on the relevant party’s list of candidates.

This voting system is used to ensure the overall Assembly reflects how all of London votes.

For more information about the different voting systems, download the factsheet below.


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