Britain, once known for long-serving prime ministers like Margaret Thatcher and Tony Blair, now sees leaders coming and going in rapid succession. The country is on course for its seventh prime minister in a decade, with Liz Truss lasting only 49 days and Keir Starmer barely two years. Several factors explain this instability, including social media hardening divisions, Brexit cutting across party lines, and a run of poor leadership. However, the deeper problem lies in the fraying relationship between prime ministers and their own MPs. Since the 1970s, MPs have become more willing to rebel, challenge leaders, and even remove them between elections. This has created a modern British habit: of the last five prime ministers, four were ousted by internal party pressure rather than voters.