Reform win sets new record for smallest by-election majority since 1945

Reform’s victory at Runcorn & Helsby by just six votes has set a new record for the smallest majority at a parliamentary by-election since the end of the Second World War.

Sarah Pochin took the seat with 12,645 votes, just ahead of Labour’s Karen Shore, who received 12,639.

She becomes only the third person in modern times to have won a by-election by fewer than 100 votes.

Along with Alan Beith’s victory for the Liberals at Berwick in 1973, the only other instance since the war was in 1967, when Frederick Silvester won Walthamstow West for the Conservatives with a majority of 62.

Labour’s narrowest win at a post-war by-election was in 1982 at Birmingham Northfield, when they took the seat by 289 votes.

The result at Runcorn & Helsby also marks Reform’s highest-ever share of the vote in a by-election.

The swing in the share of the vote from Labour to Reform was 17.4 percentage points.

This is slightly larger than the 16.0-point swing at Hartlepool in May 2021, which was the last time Labour was defeated at a by-election, on that occasion losing to the Conservatives.

The turnout at Runcorn & Helsby, 46.2%, is the highest at a parliamentary by-election since 52.2% in June 2022 at Tiverton & Honiton, when the Liberal Democrats gained the seat from the Conservatives on a swing of 29.9 percentage points.