Over the past one hundred years, only two British prime ministers, Stanley Baldwin and Harold Wilson have left Number 10 entirely voluntarily, the electorate has voted most of them out. So why do PM’s so rarely leave office on their own terms? What happens when a prime minister’s credibility becomes weakened?  The Open University’s Dr. Richard Heffernan, Reader in Government, leads discussions and compares the administrational differences between presidents and prime ministers. Can an American president be forced out of power in the same way as a British prime minister?