More than two million to vote for Burnham successor as Manchester Mayor - as by-election to take place next month
More than two million people will be able to vote for Andy Burnham’s successor as Greater Manchester Mayor, with the by-election likely to take place at the end of July.
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The post of mayor automatically fell vacant when Mr Burnham was named as the new MP for Makerfield.
Electoral law does not allow the mayor of Greater Manchester to also be a member of parliament.
The rule takes effect “immediately” the mayor is declared the winner of a seat at Westminster, according to guidance published by the House of Commons library.
The law also states that a mayoral by-election must be held within 35 working days of the post becoming vacant.
This means the poll will need to take place before August 6, with Thursday July 30 a possible date.
Some 2.1 million people were eligible to vote at the most recent election for Greater Manchester Mayor in May 2024.
Read more: LIVE: 'Voters chose hope': Starmer congratulates Burnham on Makerfield by-election victory
Fewer than a third of voters actually cast a ballot, however, with turnout of just 32%.
Mr Burnham won 420,749 of the 663,631 valid votes cast in 2024, or 63%, with the Conservatives far behind in second place on 68,946 (10%), an independent candidate third on 50,304 (8%), Reform fourth on 49,532 (7%), the Greens fifth on 45,905 (7%) and the Liberal Democrats sixth on 28,195 (4%).
The Greater Manchester Mayor is elected by voters across 10 local authorities: Bolton, Bury, Manchester, Oldham, Rochdale, Salford, Stockport, Tameside, Trafford and Wigan.
Mr Burnham topped the poll in all 10 areas in 2024.
The by-election is likely to cost several million pounds.
Figures published by the Greater Manchester Combined Authority in its budget report for 2024/25 show spending on the May 2024 mayoral election was £4.6 million.
The 2024 election took place under the first-past-the-post system, where the candidate with the most votes is declared the winner.
But the by-election for Mr Burnham’s successor is due to be held using a different method called supplementary vote (SV), following a recent change in the law.
Under SV, voters mark their ballot papers with a first and second preference.
If any candidate wins more than 50% of first preference votes, they are declared the winner.
But if no candidate has more than 50% of first preferences, all but the top two are eliminated from the count and the second preference votes come into play.
If any second preference votes of the eliminated candidates were for the two remaining candidates, these votes are then added to their first preference totals, to produce a final result.
The SV system was used for the elections of mayors and police and crime commissioners in England up to 2022, when the previous Conservative government changed the law to introduce first-past-the-post.
Labour recently reversed this change through the English Devolution and Community Empowerment Act 2026.
The Act allows for SV to be reintroduced for mayoral elections – and the Government confirmed in May this change would be in force in time for the Makerfield by-election.
Mr Burnham was elected as Greater Manchester Mayor under the SV system in 2017 and again in 2021, before winning his third election in 2024 under first-past-the-post.