The issue of the United Kingdom withdrawal from the European Union had been ongoing for many years before the 2010 general election, arguably since the 1975 United Kingdom European Communities membership referendum. In 2013 David Cameron pledged to renegotiate the United Kingdom's terms of membership with the European Union. In May 2013, the Conservative Party published a draft EU referendum bill and outlined their plans for renegotiation and then an in-out vote if returned to office in 2015. The draft bill stated that the referendum must be held no later than 31 December 2017. The draft was taken forward as a private member's bill in the House of Commons by the Conservative member James Wharton who had come top of a ballot of backbench MPs, entitling him to introduce a bill during the 2013–14 parliamentary session. His bill attempted to enshrine the Conservative Party Position into law before the 2015 general election. A spokesman for prime minister and Leader of the Conservative Party, David Cameron, said he was "very pleased" and would ensure the bill was given "the full support of the Conservative Party".