Boris Johnson wants to give his father a knighthood. How very classical of him! Xenophon said that it was ‘the mark of a man to excel his friends in benefaction and his enemies in harm’ and no one was more of a friend than a man’s father. This mantra to do good to your friends and harm to your enemies was endlessly and publicly repeated (so litigation between family members and injustice against a relation caused great embarrassment).

But how did one make friends beyond parents and kinsmen? Mutual benefit was the answer, the argument being prudential. Pericles argued that Athenians stood out from the crowd in this respect: ‘We acquire friends not in consequence of what they do for us but what we do for them… he who takes the initiative is a firmer friend… we alone confer benefits without the need to calculate our own interests first.’

As for enmity, Athenians took that for granted. Demosthenes described how he was accused of killing his father, which made his accuser ‘an enemy for life’. When his accuser was charged with defrauding the city, Demosthenes took on the case: ‘I regarded the man who had wrongfully put me into such a predicament as an irreconcilable enemy. Seeing that he had wronged the city, I proceeded against him in the belief that I had the chance to defend our interests and at the same time obtain revenge for what he had done to me.’ And when the Athenians were attacking Sicily, the Syracusan general said to his troops: ‘It is entirely acceptable to satisfy one’s anger in vengeance against the aggressor; retaliation upon enemies is proverbially the greatest of pleasures.’

Such language all sounds rather un-English. Think again. Cowardly users of social media revel in it, making a mockery of civilised debate and hurling ignorant and vicious abuse, usually involving Nazis, that they would never dare to do face to face, as they did in the ancient world.

Anyway, despite the flak, it is worth a try, Mr Johnson. After all, the emperor Caligula thought seriously about making his horse consul…