The last time the UK burnt through prime ministers at a similar rate was in decade-long stretches in the 18th century (1760–1770) and the 19th (1827–1837).

Political chaos has engulfed Britain, with six people holding the U.K.'s top job in a decade, including one prime minister who lasted only 45 days.

As the UK approaches the 10th anniversary of the June 2016 Brexit referendum, it is fair to say that the ghosts of its divisive and ruinous implications persist, despite many…