Camden Council said turnout in the Holborn and St Pancras by-election on 8 October 2026 was 38.76%, below 40%, and the Guardian reported the same 38.7%.
The turnout market resolves on the figure declared by Camden's returning officer in the early hours of 9 October and published by the council, the same source that recorded 54.46% in the seat in 2024. Turnout above 40.0% resolves YES and exactly 40.0% resolves NO, with the Electoral Commission's certified result governing any revision and the BBC and the Guardian results pages standing in if the council figure is slow.
We looked at UK byelections since 2012 where the leader of a national party stood in person, and checked whether more than 40% of voters turned out. We found six. Four passed 40%, and none passed 51%.