Uxbridge and South Ruislip is a constituency in Greater London represented in the House of Commons of the UK Parliament. The seat has been held by the Conservative Party since its 2010 creation. Since 2015 it has been represented by Boris Johnson, who served as Prime Minister of the United Kingdom from 2019 to 2022. Johnson's 2017 majority in Uxbridge and South Ruislip was 5,034 votes which was less than half his 2015 majority. After his election as Prime Minister, in the subsequent 2019 election Johnson retained the seat with an increased vote share of 52.6% and a majority of 7,210. An estimate by the House of Commons Library puts the Leave vote by the constituency in the 2016 referendum at 57.2% and The Observer reported in August 2018 that 51.4% of voters supported Remain. History The Conservative party won in 2010 and 2015 by a margin of about 25%, and since 1970 the fourteen parliamentary elections in this constituency and its predecessor (the constituency of Uxbridge) were won by the Conservatives. The 2015 result gave the seat the 149th smallest majority of the Conservative Party's 331 seats by percentage of majority. In 2010, for the Uxbridge-born Conservative candidate John Randall, the one-party swing in the seat was 0.1% greater than that seen nationally – enough on the newly drawn constituency boundaries to provide 48.3% of the vote, and a majority of more than 11,000 votes. In the 2010 and 2015 elections three (of 8 and 13 candidates respectively) attained 5% of the vote or more, to retain their deposits. In 2014, Boris Johnson was selected to run in the seat; he was elected in 2015 with a swing of less than 1% to Labour and 50.2% of the vote. However, the 2017 election saw a 13.6% increase in Labour's vote share, although Johnson also increased his votes, which reduced Johnson's majority to only 5,034, less than half his 2015 margin and by far the lowest for a Conservative candidate in the area since 2001. 2019 election Boris Johnson became Prime Minister of the United Kingdom on 24 July 2019 following the resignation of Theresa May. His 2017 majority in Uxbridge and South Ruislip of 5,034 votes was the smallest of any sitting prime minister since 1924. The main challenger to the seat was the Labour Party, whose 2019 candidate was Ali Milani. In April 2019, think-tank Onward classified the