United Kingdom general elections overview

The period from 2015 to 2019 was one of the most turbulent periods in British electoral history. Following the Conservative-Liberal Democrat coalition, the Conservatives, led by David Cameron, won the 2015 general election with a small majority, having promised to hold a referendum on continued membership of the European Union. This election saw the decimation of the Liberal Democrats, with their vote falling from 23% to 8% and MPs elected from 57 to just 8. In terms of the popular vote, they were replaced as the third party by the UK Independence Party, achieving 13%, although they won only 1 seat. The Green Party also achieved their best ever result with 4% of the popular vote. In Scotland, a resurgent Scottish National Party gained 50% of the popular vote, winning all but three of the 59 seats, mostly at the expense of the Labour Party.

Following the EU referendum held in June 2016, which resulted in a majority of 52:48 to leave, David Cameron resigned as Prime Minister and was replaced by Theresa May. In June 2017, Mrs May called a snap election; however, following a disastrous election campaign, the Conservatives lost their overall majority and had to rely on the support of the 10 MPs from the Democratic Unionist Party to continue in Government. The following two years were dominated by attempts to pass through Parliament a negotiated deal on the terms for leaving the EU, but these were opposed by both ardent "Brexiteers" and "Remainers" in the Conservative Party, as well as the Opposition parties. Eventually, Mrs May resigned and Boris Johnson was appointed as Prime Minister.

After further Government defeats, a general election was finally held in December 2019 - the first December election since 1923 - which resulted in an 80 seat majority for the Conservatives, gaining many seats which Labour had held since at least 1945. The United Kingdom formally left the European Union on 31 January 2020.

This period saw just five prime ministers, with Margaret Thatcher and Tony Blair the two longest serving post-World War II prime ministers [1] in the UK (the other prime ministers during this period being John Major, Gordon Brown and David Cameron). There was also a mini-revival of the Liberal Party which, after a merger with the Social Democratic Party became the Liberal Democrats and increased their seats in parliament from 11 in the 1979 election to 62 in 2005.

Following their victory in 1979, the Conservatives were also successful in the subsequent three general elections, resulting in 18 years of continuous power. The newly formed Social Democratic Party and the Liberal Party contested the 1983 and 1987 elections as the SDP-Liberal Alliance. Although the combined parties achieved a popular vote of 22.6% in 1983, they initially failed to make a breakthrough in terms of seats, winning just 22.

The Labour party won a landslide victory in 1997 and were also successful in 2001 and 2005. The now merged Liberal Democrats also improved their seat count in this period. The outcome of the 2010 election brought about the first hung parliament since 1974 and forced the victorious Conservative Party to accept the Liberal Democrats as their coalition partner.

In Northern Ireland, the Good Friday Agreement has led to a vast reduction in conflict, though the traditional parties who gained power in the 1980s, such as the Ulster Unionist Party, have been replaced as the dominant powers by the likes of Sinn Féin and the Democratic Unionist Party.

The elections of the 1990s and 2000s (decade) also saw an increased proliferation of smaller parties, with more parties standing at the 2005 general election than ever before.[2] Voter turnout also fell during this period, with the 2001 election seeing a post-World War II low of 59.4%.[3]

The elections of this period took place in the context of the decolonialisation of the British Empire and the UK's declining status as a Great Power.[4] It also saw the UK enter the European Union and some periods of high unemployment.[5] The early years of the period saw Conservative consolidation of power, before Harold Wilson's two general election wins in 1964 and 1966. There was then a series of close fought elections, including two in 1974. This period was also the one in which the Liberal Party was at its all-time low, never having more than 14 seats (though it had been in 1951 when they'd had their lowest ever percentage of the vote).

The Ulster Unionists dominated in Northern Ireland, whilst the Scottish National Party and Plaid Cymru became major players for the first time, the SNP gaining 11 seats in 1974. This period also saw the demise of the autonomous Unionist Party in Scotland and the National Liberal Party, which both merged with the Conservative Party.

This era saw massive social change in the UK, going through the Great Depression of the 1930s, resulting in a National Government; the Coalition Government of the Second World War led by Winston Churchill; and the socialist Labour government of Clement Attlee.[6] This was also the period of the Liberal Party's major collapse and the completion of Labour's rise to power.

The 1929 election resulted in the Labour Party having the greatest number of seats and they formed a Government under Ramsay McDonald with the support of the Liberals. As a result of the growing economic crisis, McDonald formed a National Government in 1931 with the support of the Conservatives and Liberals, which was not however backed by the majority of Labour MPs. This was followed by a general election at which the National coalition, dominated by the Conservatives, won a landslide victory, with the opposition Labour Party reduced to a rump of 52 seats. It also led to a permanent split in the Liberal Party, with the National Liberals eventually joining the Conservatives. Although Labour recovered somewhat, the (notional) National Government won the 1935 election.

General elections were suspended during the Second World War, when all three major parties entered into a coalition under Churchill. The Labour party gained a landslide victory in 1945. Although they won a small majority in the 1950, they were defeated by the Conservatives in 1951, with Churchill returning to power.

In the years after the secession of the Irish Free State, the Conservatives led the House of Commons, followed by a surging Labour Party and a declining Liberal Party. The Communist Party of Great Britain also enjoyed their most prolonged period of success, though still failed to have more than 1 MP at any time.

The 1922 election was won by the Conservatives, with the Labour party in second place and the Liberals split. In 1923, the Conservatives lost their majority and the Labour Party were put into office for the first time with the support of the re-united Liberals. However, this minority government only lasted 10 months and the 1924 election saw the return of the Conservatives with a large majority and the Liberal Party reduced to a rump of 40 MPs, from which they never really recovered.

• Elections in the United Kingdom
• List of United Kingdom general elections

• House of Commons Library: "UK Election Statistics: 1918-2019 - A century of elections"