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.

Local elections took place in 181 local authorities on 3 May 2012. Almost 4,900 council seats were up for election in 128 local authorities in England, 32 unitary authorities in Scotland and 21 unitary authorities in Wales.
Local elections 2012 (1 MB , PDF)
Local elections took place in 181 local authorities on 3 May 2012. Almost 4,900 council seats were up for election in 128 local authorities in England, 32 unitary authorities in Scotland and 21 unitary authorities in Wales.
Labour made net gains of 32 councils and over 800 council seats. The Conservatives had a net loss of twelve councils and 400 seats. The Liberal Democrats had a net loss of more than 300 seats and one council.
Labour won 39% of the national equivalent share of the vote, compared to 33% for the Conservatives and 15% for the Liberal Democrats. Turnout was estimated to be 32%.
There were inaugural mayoral elections in Liverpool and Salford. Ten cities held referendums on whether to introduce directly elected mayors, with only Bristol voting in favour. In Doncaster, voters decided to retain the office of mayor in a referendum on whether the mayoral system should continue.
Local elections 2012 (1 MB , PDF)
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 sets out results of the by-elections held in the 2019 Parliament. Full details are presented in the associated PDF but an overview of the recent by-election results are shown below.
A briefing paper on the legal issues surrounding a Scottish independence referendum