The Mayor of London, Boris Johnson, as has  often been remarked, is one of few British politicians widely known by only his first name. He owes that in part to his parents’ choice of a name that is relatively unusual here. A Dave or a Nick, however flamboyant, will find such instant name recognition harder. But it is also because of his distinctive appearance and, yes, his personal charisma. Rightly or wrongly, he comes across as a sympathetic human being. 

He also appears to be rather good at certain other things that would generally be thought less socially and politically acceptable. These include his wandering eye and fathering a child by a woman other than his wife. It was lawful, a judge found recently, for this to be reported, because Mr Johnson’s “recklessness” had a bearing on his fitness for public office. The inference was that if and when Boris seeks higher office – such as the job of Prime Minister some say he covets – voters might want to take his personal behaviour into account.

But will they? A ComRes poll, commissioned by The Independent showed that it would make almost no difference at all. A whopping – to use a Boris word – three quarters of those asked said it would not make it any less likely that they would vote for him in a general election. A further 9 per cent said they did not know whether it would affect their vote.

Several glosses can be put on this finding. One is that British society is now much more forgiving of personal behaviour that would once have been condemned, and that this tolerance extends to politicians. Another would be that voters treat Mr Johnson rather like Nigel Farage, as a politician not to be taken seriously.

But a third possibility is that people allow their personal liking to override their disapproval. In other words, Boris has a gift, akin to that of Bill Clinton, that allows him to break all the rules of electability. Whatever interpretation is correct, one conclusion is clear: his political enemies will need to find a stick other than infidelity with which to beat him.