Donald Trump’s Twitter feed was oddly silent as the news came that his former campaign manager and his former lawyer were going to jail. Perhaps his staff have finally seized control of his phone. Perhaps his lawyers have convinced him that every time he tweets on anything relating to the Russia investigation, he is dancing on a precipice, with special counsel Robert Mueller just waiting to push him off. Whatever the reason, this was the equivalent of Trump entering a stunned, catatonic state, while his world spins out of control around him.

Imagine if Theresa May suddenly announced that her government was going to devalue the pound by 96 per cent; increase the minimum wage by 6,000 per cent; pay the wage increases for millions of businesses for three months; tie the pound to a mythical cryptocurrency; prepared for petrol rationing; and impose a 0.7 per cent tax on big financial transactions. It would be seen either as an act of lunacy, of a collapsing country — or both.

It is hard to think of a code of behaviour which is common to all societies on earth, let alone to most other species too — except, that is, for the avoidance of incest. Even cockroaches have developed a breeding strategy that prevents them mating with their own siblings. And yet as we understand more about the genetic dangers of inbreeding, so the social infrastructure that guards against it is being dismantled. In the 40 years since the birth of Louise Brown, the world’s first test tube baby, births by IVF have become routine — almost 2,500 a year using donated eggs, sperm or both.

The brilliant Irish comedian Andrew Maxwell describes doing stand-up at the Edinburgh Fringe as ‘exams for clowns’, and even though I first appeared there in 1981 (when the Cambridge Footlights Revue featured Hugh Laurie, Stephen Fry, Emma Thompson and Tony Slattery), I felt an overwhelming surge of nervousness as I began my short run this year with the peerless mimic Jan Ravens (who herself had directed that illustrious 1981 cast).