The period from 2015 to 2019 was one of the most turbulent in British electoral history. Following the
Conservative–Liberal Democrat coalition, the
Conservatives, led by
David Cameron, won the
2015 UK general election with a small majority, having promised to hold a referendum on continued membership of the
European Union. This election saw the
Liberal Democrats' vote fall from 23% to 8%, and the number of elected Lib Dem MPs dropped from 57 to 8. In terms of the popular vote, they were replaced as the third party by the
UK Independence Party, who achieved a 13% vote share, although they won only one seat. The
Green Party also achieved their best ever result with 4% of the popular vote. In Scotland, the
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, Cameron resigned as
Prime Minister and was replaced by
Theresa May. She called a
snap election in June 2017, but the Conservatives lost their overall majority and had to rely on the support of the ten 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
Brexiteers and
Remainers in the Conservative Party, as well as the
opposition parties. May eventually resigned and
Boris Johnson became prime minister. After further government defeats, a general election was held in
December 2019—the first December election since
1923—which resulted in an 80-seat majority for the Conservatives, gaining many seats that Labour had held since at least
1945. The United Kingdom formally left the European Union on 31 January 2020. ==1979–2010==