At the 2001 general election, David Cameron was elected as MP for Witney. Cameron was re-elected to a fourth term as MP for the constituency at the 2015 general election with a majority of 25,155, the highest in his political career; on that occasion his Conservative Party won a surprise overall majority in the House of Commons, taking 330 seats to the opposition Labour Party's 232. However, on 24 June 2016, Cameron announced that he would resign as Prime Minister by that October due to the outcome of the EU Referendum the previous day, in which 51.9% of voters supported leaving the EU. On 12 September 2016, it was announced that Cameron would resign as MP for Witney. This triggered a by-election, which was won by Robert Courts, also a Conservative, albeit with a significantly reduced majority.