As Boris Johnson left No 10, he possibly gave the officials and supporters gathered in Downing Street an obscure hint about what his future might hold.

“Let me say that I'm like one of those booster rockets that has fulfilled its function,” he said. “And I will now be gently reentering the atmosphere and splashing down invisibly in some remote and obscure corner of the Pacific. Like Cincinnatus, I am returning to my plough."

As the outgoing Prime Minister, who read Classics at Balliol College, Oxford, will know, Cincinnatus was a fifth century BC Roman politician, who ended his retirement when Rome was threatened with a military invasion.

He took up the dictatorship, defeated the enemy, and then went back to his farm. All within 15 days.

“He's often treated as an absolute hero,” The classicist Mary Beard explained to Radio 4’s Today programme. 

“The man who comes in, saves the state, but doesn't take power for himself long term, but goes back to his plough.”

“But it wasn't quite so simple,” the Cambridge professor added. “Because one thing you need to know about Cincinnatus is that he was absolutely resolutely anti-populist.

“He completely opposed the rights of the poor and the unprivileged in Rome. He was, in our tems, extremely right wing. 

“There is also an even worse sting in the tail, in that there's another story, which says after he saves Rome, and a decade or so later, he comes does come back to power again, very briefly. 

“Why does he come back to power? to suppress a popular uprising by the underprivileged.” 

It was, Professor Beard, added, “a risky analogy.”