Labour won Holborn and St Pancras on 8 October 2026 with 12,292 votes to the Greens' 8,928, a majority of 3,364, under 5,000, as BBC News and the Guardian reported; Camden's full results page could not be read because it blocks automated visits.
The margin market resolves on the same declared figures: YES if Labour's majority over the second-placed candidate is fewer than 5,000 votes, and YES as well if Labour does not win, because there is then no Labour majority to count. Where early reports and the Electoral Commission's certified result differ, the certified result governs, with the BBC and the Guardian as the backup record.
We looked at byelections since 2010 in seats the governing party had won at the last general election, in the first three years of a parliament. This one comes 26 months into the parliament elected in 2024. We show the last eight. The governing party kept two of them.