Will the total number of UK parliamentary by-elections with polling day scheduled and held in 2026 be at least 5 2026

30-day trend

Analysis

This market reflects strong confidence that the UK will hold at least 5 parliamentary by-elections before the end of 2026, with traders pricing this outcome at 93%. The probability is elevated because the Labour government under Keir Starmer faces a narrow Commons majority achieved in July 2024, creating structural conditions for vacancies through retirements, scandals, or defections. Factors that could increase the probability include potential Labour backbench rebellions or strategic exits, while a sharp drop would require unexpected stability in the Commons. The main uncertainty driver is the unpredictable timing of individual MP retirements and resignations. By December 2026, the market will resolve based on the final count of all by-elections with polling days held during the calendar year, providing clear evidence of whether the baseline expectation of frequent turnover materializes.

• ›Labour's working majority of approximately 3-20 seats (depending on speaker and sickness) makes the government mechanically vulnerable to by-election losses
• ›Historical baseline: the UK averaged 6-8 by-elections annually during the 2015-2024 period, though this varies widely
• ›Pricing shows near-identical confidence (93%) for both 'at least 5' and 'at least 6', but sharply lower confidence (80%) for 'at least 8', suggesting clustering around 5-7 expected by-elections
• ›The market opened after the July 2024 election, so traders are forecasting typical turnover patterns under current parliamentary arithmetic
• ›By-election frequency depends on voluntary retirements, deaths, and forced resignations—none of which follow a predictable schedule

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These markets stopped trading. Last odds and any captured outcome are shown above — full settlement detail lives at the venue.

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