Number of MPs changing party allegiance in a  parliamentary term, 1979–2025

Source: Institute for Government analysis of House of Commons Library 'MPs’ changes of party allegiance in the House of Commons since 1979'Notes: Includes duplicate MPs that changed party allegiance more than once in a parliamentary term. 'Removed' includes MPs that were suspended or had the whip removed. 2024 parliament correct as at 15 September 2025Get the dataEmbed Download image
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