"Every decision I have taken has been about putting the country I love first. That is why I will resign as leader of the Labour Party," Starmer said as he choked up in an emotional speech outside 10 Downing Street.
Starmer said the process of picking a new Labour Party leader would be launched in July and he would remain as prime minister until his successor is chosen, to be in place in September.
Keir Starmer: British PM fighting for his political future