Why PMs get the push

Boris Johnson’s fall as prime minister early in July was spectacular. It was forced, not by any formal vote, but instead by the resignation of dozens of ministers and aides following a series of damaging political scandals. Indeed, the number of resignations was so great that, had Johnson not quickly reversed his refusal to step down, the business of government might have ground to a halt. In keeping with Johnson’s taboo-breaking career, the cascade of ministerial departures was unprecedented – but history shows us that the enforced termination of a premier’s occupancy of Downing Street is a much more commonplace occurrence.

Of the 20 men and women who have held the keys to Number 10 since the First World War and the dawn of the era of mass enfranchisement, only six have had their prime