Before last Wednesday humbug had fallen out of favour from parliamentary usage. MPs used the word, on average, once every 127 days since 2010. But the term has been freely bandied about since last week, after Boris Johnson disreputably accused Paula Sheriff, a female Labour MP, of “humbug” because she had complained about the death threats she receives which quote his words. Originally slang from the 18th century that became common currency in Victorian England, humbug was best defined by the philosopher Max Black as an act of “deceptive misrepresentation”. Describing someone’s speech as humbug is not calling them a liar. It is, in some ways, worse. A liar and a truth-teller both respond to the facts. An honest person is guided by the authority of the truth, while a liar defies that authority. A humbugger pays no attention to the truth, preferring their own reality. Mr Johnson is probably the most successful humbugger in British political life.

The prime minister revels in a form of scepticism that denies the idea that the public can have any reliable access to the truth and therefore we ought to reject the possibility of knowing, with any accuracy, how things are. Mr Johnson’s political strategy is to harden others’ positions and define compromise as defeat. He wants leavers to believe that a cost-free version of Brexit exists, which they are being denied through parliamentary incompetence and conspiracy. Mr Johnson trades in an unsubtle level of insinuation and threat. To MPs who defy him, and resist getting Brexit done by 31 October he warns that the country will remain “divided and angry”. This is hardly a person who wants to bring the country together by taking into account the diversity of views around Brexit. It is more like a mob boss saying “that’s a nice country you have, it would be a shame if something happened to it”.

This strongman image has been carefully cultivated. Mr Johnson’s doctrine seems to be whatever the prime minister does is by definition legal. If parliament attempts to compel him to extend Brexit to avoid a damaging no deal, Mr Johnson does not dissuade his audience from thinking there are wheezes available to him to dodge the law. He raises the possibility of a “backlash” against the supreme court because it dared, correctly, to void his decision to suspend parliament for five weeks at a moment of crisis. Mr Johnson plainly believes he has the right to ignore investigations against him. And to Ms Sheriff he offered a classic non-apology about being “sorry” if anyone misunderstood his words.

Mr Johnson appears to do anything for a crowd, gleefully dismissing “gloomsters” with the farcical promise of Brexit’s sunlit uplands. His political persona is well suited to being a fake tribune of the people. Mr Johnson isn’t bound by the truth. When he is not fabricating, he is exaggerating. It is a symptom of the current Brexit malaise that so many people seem willing to be taken in by Mr Johnson, provided there is entertainment to be had. The 2016 referendum was driven by conspiracy theories suggesting the EU had hidden plans to be a superstate, that it wanted an army and the vote would be rigged. The political and economic impacts of leaving the EU were – and still are – shrouded in conspiracy. Mr Johnson’s eye is not on the facts. There is no credible deal with the EU on what Mr Johnson said were “abundant, abundant technical fixes” for the Irish border. The prime minister seems unfazed by the prospect of food and medicine shortages and public disorder envisaged by government officials. The facts are only pertinent to Mr Johnson’s interest in getting away with what he says. He does not care whether his words describe reality correctly. It is a tragedy that he can so easily just pick them out, or make them up, to suit his purpose whatever the cost to the country.