The moment of succession is the midnight of the state, a period of maximum danger, the hour when power passes from incumbent to novice, when experience gives way to uncertainty. To preserve stability, traditional states used to insist on a speedy succession: “The king is dead; long live the king.” In modern democracies, speed has been sacrificed to legitimation by popular mandate. But in China today, speed has been sacrificed, but without legitimation, for there is no longer an accepted procedure by which an heir apparent is chosen.

In Mao Zedong’s day the Chairman chose or dispensed with putative successors as he saw fit. After 20 years in the No 2 slot, Liu Shaoqi was purged in 1966. Five years later his successor, Marshal Lin Biao, was hounded into fleeing the country, dying when his plane crashed in Mongolia. The young Shanghai revolutionary Wang Hongwen was helicoptered into Beijing to take Lin’s place, but Mao soon found he was not up to the job.

Finally, Mao chose the unremarkable Hua Guofeng, who did succeed him. But Hua declared loyalty to his patron’s disastrous Cultural Revolution policies and, within five years, Deng Xiaoping was able to deprive him of all his posts.