Rishi Sunak Becomes UK's New Prime Minister. Rishi Sunak Rishi Sonik has become Britain's third prime minister in less than two months - and the fifth in six years. These are the fastest changes to the British Prime Minister's House in nearly a century. Since the summer of 2007, Gordon Brown, David Cameron, Theresa May, Boris Johnson, Liz Truss, and Mr. Sonnick have all held the office of Prime Minister. By contrast, in the 28 years before 2007, only three Prime Ministers had been elected - Margaret Thatcher, John Major and Tony Blair. Why are the doors of the Prime Minister's House, called 'Number 10' in Britain, spinning so fast now, what is the reason for this? And could this trend of rapid change become the new normal for British politics? A panel of experts opined on why it is becoming so difficult for a prime minister to stay in office. Jill Rutter, associated with the British think tank 'Institute for Government', believes that the Brexit vote in