The parallels between current political upheavals in Britain and the United States were wittily pinned down by William Hague, former Tory leader, when he called those fighting to pull Britain out of the European Union “the Trump campaign with better hair”. The explanation for this remark is that Boris Johnson, the Brexit campaigner with the highest profile, while equally blond, has the finer mane. Donald Trump, the prospective Republican nominee for the presidency of the United States, is barely able to conceal, by judicious comb-over, that he is becoming thin on top. Indeed it is a metaphor for his whole philosophy.

Unruly straw-coloured hair may not be where the similarities end. Both Boris Johnson and Donald Trump have been surfing a wave of anti-establishment feeling. Mr Trump hopes to ride it all the way to the White House by branding Hillary Clinton, who is almost certain to be his Democrat opponent, as the product of an elite political class.