Boris Johnson hails election triumph

The 2019 United Kingdom general election was held on Thursday 12 December 2019 under the provisions of the Early Parliamentary General Election Act 2019 (EPGEA), two-and-a-half years after the previous general election in 2017. The governing Conservative Party achieved a landslide majority of 80 seats in the House of Commons after having lost it in 2017, while the Labour Party suffered major losses that resulted in it obtaining its lowest proportion of seats since the 1935 general election.

The Conservative Party, having failed to obtain a majority in the 2017 general election, had faced a prolonged parliamentary deadlock over Brexit while it governed in minority with the support of the Democratic Unionist Party (DUP). In July 2019, Boris Johnson was elected as the Conservatives' leader and appointed as Prime Minister, after Theresa May resigned. Johnson could not get Parliament to approve a revised withdrawal agreement by the end of October, and chose to call for a snap election. The House of Commons voted by 438–20 in support of this, and the EPGEA became law on 31 October 2019. Johnson needed to obtain an overall majority in the election in order to accomplish his main goal of taking the United Kingdom out of the European Union by the end of January 2020. Opinion polls showed a firm lead for the Conservatives against Labour throughout the campaign.

 At the election, the Conservatives made a net gain of 48 seats, in what was regarded as a landslide victory across the English constituencies, winning 43.6% of the vote (the highest share for any party since 1979) and 365 seats (the highest number for the party since 1987). The party won 345 seats in England, and 14 seats in Wales: both increases on 2019. Labour made a net loss of 60 seats, mostly to the Conservatives in northern England and across the Midlands. Labour's losses in the general election led its leader Jeremy Corbyn to announce his intention to resign as the party's leader. The Liberal Democrats increased their share of the votes to 11.6%, but their leader Jo Swinson was obliged under her party's rules to announce her resignation after losing her seat in East Dunbartonshire, leaving her party with 11 seats. The Green Party held its one seat and saw its vote share increase. Just like in 2015 and 2017, four different parties won the most seats across the four countries of the United Kingdom.

Theresa May began 2019 as the Prime Minister of the United Kingdom. The second May ministry was unable to pass the Brexit withdrawal agreement by 31 March 2019, so some political commentators considered that an early United Kingdom general election was likely. The opposition Labour Party called for a January 2019 vote of confidence in the May ministry, but the motion failed. After May resigned after the 2019 European Parliament election, during the first extension granted for negotiations on the withdrawal agreement, Boris Johnson won the 2019 Conservative Party leadership election and became prime minister on 23 July 2019. Along with attempting to revise the withdrawal agreement arranged by his predecessor's negotiations, Johnson made three attempts for a snap election under the process defined in the Fixed-term Parliaments Act 2011, which requires a two-thirds supermajority in support of this.

 All three attempts failed to gain support, while Johnson faced increasing pressure to secure a deal for the United Kingdom, following the enactment of the European Union (Withdrawal) (No. 2) Act 2019 (referred to as the "Benn Act") which prevented him from taking the country out of the EU without a deal. After failing to pass a revised deal before the first extension's deadline of 31 October 2019, Johnson was forced to call for a second extension on negotiations from the EU, and agreed upon holding a vote in the House of Commons for a snap election through a proposal forwarded by the Liberal Democrats and Scottish National parties on 28 October. The Early Parliamentary General Election Act 2019 (EPGEA) won a majority in the Commons by 438 votes to 20; an attempt to pass an amendment by opposition parties for the election to be held on 9 December failed by 315 votes to 295. The House of Lords followed suit on 30 October, with Royal Assent made the day after for its ratification. 

The Conservative Party won a landslide victory securing 365 seats out of 650, giving them an overall majority of 80. The Conservatives gained seats in several Labour Party strongholds in Northern England, flipping seats that were held by Labour for decades. Bishop Auckland elected a Conservative for the first time in its 134-year history as constituency. In the worst results for the party in more than 80 years, Labour lost a total of 59 seats reducing them to 203 seats. The Liberal Democrats failed to gain the results they had hoped for: they both lost and won seats, for a net reduction of 1, reducing them to 11 seats in the new parliament. The Scottish National Party gained 13 seats, winning 48 of the 59 seats in Scotland. The SNP's leader Nicola Sturgeon described the result as a clear mandate to hold a new referendum for Scottish independence.