On 30 June 2016, May announced her candidacy for the leadership of the Conservative Party to replace David Cameron, who resigned following the outcome of the European Union membership referendum in which 52% of voters voted in favour of leaving the EU. May emphasised the need for unity within the party regardless of positions on leaving the EU, saying she could bring "strong leadership" and a "positive vision" for the country's future. Despite having backed a vote to remain in the EU, she insisted that there would be no second referendum, saying: "The campaign was fought... and the public gave their verdict. There must be no attempts to remain inside the EU, no attempts to rejoin it through the back door... Brexit means Brexit". An opinion poll that day found 47% of people choosing May as their preferred candidate to be prime minister.