On 11 May 2010, following the resignation of Gordon Brown as Prime Minister and on his recommendation, Elizabeth II invited Cameron to form a government. At age 43, Cameron became the youngest British Prime Minister since Lord Liverpool, who was appointed in 1812.

Cameron was elected as the Leader of the Conservative Party and Leader of the Opposition was announced on 6 December 2005.

The Conservatives had not won a general election since 1992. The general election of 2010 resulted in favour of the Conservatives, led by Cameron, winning the largest number of seats. Among Cameron's first actions was forming a pact with Liberal Democrat Leader Nick Clegg—a move that resulted in the first coalition government since World War Two.