UK parliamentary by-elections since 1945
This list notes the number of by-elections by session since 1945-46 and also lists the successful candidate in by-elections since 2005.

This list notes the number of by-elections by session since 1945-46 and also lists the successful candidate in by-elections since 2005.
This Commons Library briefing paper presents an overview of UK election results since 1918. It provides summary results for all elections from 1918 to 2022, giving more extensive details about UK general elections. It also includes elections to the European Parliament, devolved legislatures and local government.
Constituency-level data on electorates in the UK, including data for both the parliamentary and the local government franchise
Explore the 2021 local election results handbook and download a comprehensive results dataset for English electoral districts and wards.
Data Dashboard
Search the results of the 2019 General Election for each constituency using the interactive dashboard
Research Briefing
This dataset presents UK general election results by constituency from 1918 onwards. It draws on several sources, described below, which may contain errors. For each constituency, the dataset includes the number of votes and vote share for different political parties, as well as the electorate and turnout. Turnout was calculated as valid votes divided by the electorate.
Research Briefing
This Commons Library Briefing Paper sets out results of the by-elections held in the 2017 Parliament. There were five by-elections in the two year Parliament, details can be found in the report. Full details are presented in the associated PDF but an overview of the recent by-election results are shown below.
Research Briefing
This Commons Library Briefing Paper analyses the results of the 2019 General Election. It provides maps, charts and tables showing winners, votes, vote shares and turnout by party, region and constituency.
Research Briefing
This briefing paper contains detailed results and analysis of the 2017 General Election, held on 8th June. It provides election results by party & constituency, as well as analysis of voter trends, MP characteristics, and more.
Research Briefing
A by-election takes place in the House of Commons when a seat becomes vacant, either through the Member of Parliament dying or resigning the seat. This list notes by-elections that have taken place more than three months after the vacancy.
Research Briefing
This briefing paper analyses the results of the 2015 General Election. It includes the election results by country, region and party, as well as the full result and turnout for every UK constituency. This is the second edition of the briefing paper, which provides additional analysis and statistics. New chapters in this edition cover seats changing hands, the characteristics of voters for each party, the characteristics of candidates and MPs, the electorate and turnout, safe and marginal seats, by-elections during the last Parliament, polling day, and the marginality of constituencies. The full results are available for download in two CSV files. The election results shown in this Briefing Paper were provided by Returning Officers following the 2015 General Election.