Sir Keir Starmer could be heard choking up as he stood outside Downing Street and announced he will be resigning as the UK's prime minister, less than two years after he won a significant majority at the last general election.His resignation triggers a leadership contest in the Labour party, the winner of which gets to become the UK's seventh prime minister in around 10 years.Addressing the nation, Starmer said becoming prime minister two years ago had been the 'proudest moment of his life' and talked about the 'hard work of change', listing off some of the achievements of his government...