Following a manifesto commitment, Cameron and the Conservative Party introduced legislation for a referendum on the UK's membership of the European Union, which was held on 23 June 2016. Cameron and the Government supported a Remain vote, although the Conservative Party was officially neutral in the campaign and many Conservative politicians, including some Cabinet members, campaigned to Leave. There was speculation during the campaign as to whether Cameron would resign if Leave won, but on the day of the referendum, both Leave- and Remain-supporting Conservatives called for him to stay whatever the result.