In May 2015 the Conservative Party led by then Prime Minister David Cameron won a small but unexpected overall majority in the 2015 UK general election which contained a manifesto promise to hold a renegotiation of the UK's membership of the EU to be followed by a in-out referendum. It was fulfilled when the Referendum Bill was contained in the Queens speech three weeks after the election with both Labour and the Liberal Democrats dropping their previous opposition. The renegotiation was completed in February 2016 and the referendum was held on 23 June of the same year in which 51.9% of voters chose to Leave the European Union compared with 48.1% of voters who chose to Remain a member of the European Union.