UK general election results for Parliament from 1802, the first election after the union between Great Britain and Ireland, to the 2017 hung parliament, in which the Conservatives lost their majority. Prior to 1832, when the Great Reform Act extended the franchise and reformed constituencies, the figures are only speculative estimations based upon very sparse data available, and are therefore not definitive.
The gains or losses for each party generally reflect the changes relative to the number of seats entering the election, not the number of seats won at the previous election. Between 1802 and 1832, the lack of strong, consolidated parties permitted multiple factions led by single leaders to oppose or support ministries between elections. Gauging the absolute figures of these factions or parties has proven elusive. More recently, by-elections and boundary changes would also alter these figures. Therefore, the numbers represent solely the gain upon the parliament that entered the election.
In-government seat bars are shown first, followed by the opposition and all subsequent parties. Parties share the same bar when they contest an election in coalition together.
