Recent UK parliamentary by-elections have been triggered primarily by MP resignations, with the writ moved in the House of Commons typically by the relevant party's Chief Whip or government business managers to schedule polling between 21 and 27 working days later. The most immediate contest is the Holborn and St Pancras by-election on 8 October 2026, called after former Prime Minister Keir Starmer resigned his seat to focus on international affairs following his departure from Downing Street; Labour's Chief Whip moved the writ, setting up a contest against the Green Party leader. Multiple council by-elections are also scheduled through October and November 2026 due to resignations and vacancies, including in Durham and Newark and Sherwood. Future parliamentary contests depend on additional resignations or deaths, which parties can time strategically ahead of potential general election considerations.