David Cameron, the British prime minister, has announced that he will resign following a humiliating defeat in a referendum on Britain’s membership in the European Union. Cameron’s voice cracked with emotion as he revealed he would stand down before the Conservative party conference in October, following a 48-52 defeat in the referendum that he himself called. Sterling fell overnight to a 30-year low on the news, and the FTSE 100 fell 8.5 percent at its opening, the biggest one-day drops in recent history. Cameron, who just over a year ago was returned triumphantly to 10 Downing Street with an overall majority in the general election, said he had already told the queen of his decision. Cameron said: “The British people have voted to leave the EU and their will must be respected… There can be no doubt about the result.” He said that charting a new relationship with Europe would “require strong, determined, and committed leadership,” adding, “I do not think it would be right for me to try to be the captain to take the country to its next destination.” Appearing close to tears, he concluded, “I love this country and I feel honored to have served it. I will do everything I can in future to help this great country succeed.” Favorite to land the top job is Boris Johnson, Cameron’s charismatic government colleague and former school friend who turned against him to become the de facto leader of the Leave campaign.