List of European Parliament by-elections in the United Kingdom

By-elections to the European Parliament in the United Kingdom were held during the period when the United Kingdom used single-member, first-past-the-post constituencies to elect Members of the European Parliament from 1979 to 1999: they were required when a member resigned, died or was disqualified. Six by-elections were held in this period, all retained by the holding party.

The European Parliamentary Elections Act 1999 established a new system of multi-member constituencies elected by a closed party list system based on the regions of England, plus Scotland and Wales. The single transferable vote system was retained in Northern Ireland. Because of the new system, retiring MEPs would be replaced by a different person from the list, so no further by-elections were held.

London South West
The London South West by-election took place on 20 September 1979, a few months after the 1979 election. The elected MEP, Shelagh Roberts, was disqualified for holding an office of profit under the Crown. Roberts ran again and won, but with a significant swing against them.

Midlands West
The Midlands West by-election took place on 5 March 1987. It was caused by the death of Terry Pitt, the sitting MEP. The seat was retained by Labour, with a much reduced majority.

Hampshire Central
The Hampshire Central by-election took place on 15 December 1988. It was caused by the death of Basil de Ferranti, the sitting MEP. The seat was held by the Conservatives with a large majority.

Merseyside West
The Merseyside West by-election took place on 12 December 1996. It was caused by the death of Kenneth Stewart, the sitting MEP. The seat was held by Labour with a reduced large majority.

Yorkshire South
The Yorkshire South by-election took place on 7 May 1998. It was caused by the retirement of Norman West, the incumbent MEP for 14 years. The seat was held by Labour, but saw a large reduction in the majority.

North East Scotland
The North East Scotland by-election took place on 26 November 1998. It was caused by the death of Allan Macartney, the sitting MEP. The seat was held by the SNP, with an increased majority.