Boris Johnson will have nothing to show for his divisive goading when his Brexit plans inevitably fail

Editorial: The prime minister is more than likely to wake up on 1 November with the UK still in the European Union with an even smaller and more disenchanted base than he has now

According to the now well-known parliamentary “bible”, Erskine May, “good temper and moderation are the characteristics of parliamentary language”. Well, there’s a thing.

Of course, in reality, the chamber of the House of Commons has often been a rough house, in which “grave disorder” has from time to time broken out, sittings have had to be suspended, and excitable members have lifted the mace off its usual perch and swung it around, which brings proceedings to a halt as if by some sort of witchcraft (the house cannot sit unless the mace is safely lodged in its brackets).

Still, recent proceedings in the house have been of a different and far uglier nature. Instead of the usual courtesies extended to the memory of a member of the house assassinated by a far-right extremist, and the customary rumbles of mutual concern about the death threats so many MPs now routinely receive, the prime minister saw fit to describe such fears as “humbug”. He added considerable insult by suggesting that the best way to honour the memory of Jo Cox, the late member for Batley and Spen, was to “get Brexit done”. This, despite the fact that she was killed during the 2016 European Union referendum, when she campaigned to Remain in the EU.

The word “toxic” has been used a good deal as the Brexit “debate” has dragged on and debilitated national life, but it is an appropriate one to describe what has overtaken the country’s legislative life since David Cameron unleashed the demons in 2016.

It has always been the case that there have been great issues that divided the nation, provoked huge protests, riots and legislative battles – the Iraq War, the whole experiment with Thatcherism, and especially the 1984-85 miners’ strikes; industrial strife in the 1970s; IRA and Islamist terror; riots or race riots in almost every decade; the conduct of the world wars; appeasement; Suez; the general strike; the hungry Thirties… Britain has been a far more divided and violent society than often assumed, with language to match.

However, never before has a prime minister – not even Margaret Thatcher or Neville Chamberlain at their most arrogant and aggressive, to take the most partisan leaders the British have suffered in a century – gone so far as Boris Johnson to provoke with deliberately offensive and dismissive language about opponents and fellow citizens.

The premeditation of deploying such talk, and the poisoning of the national political culture, seems clear because, even for Mr Johnson, no stranger to loose talk and careless phrasings, it is so out of character. His own sister Rachel says “it’s not the brother I see at home; it’s a different person”. To her credit, she speculates that he has been pushed into it, perhaps, by pressure from his Svengali-like adviser Dominic Cummings (a “career psychopath”, according to David Cameron) or fabulously wealthy financiers who stand to do very well out of no-deal Brexit and a collapse in sterling. Ms Johnson knows our prime minister better than most.

Thus it is, a little too obviously, a deliberate tactic on the part of the prime minister, part of his plan for a parliament versus the people general election, a set-piece contest in which all the opponents of no-deal Brexit can indeed be goaded by him into attacking his no-deal plan. And then portrayed as cowards, traitors, enemies of the people, collaborators and all the rest, as intent on what is laughingly known as the Surrender Act – in reality, the only thing standing between Britain and a protracted economic depression.

If the idea is to inflame the debate and to galvanise the Johnson “base”, Trump-style, it may not entirely succeed. For not only does such gratuitous offence motivate your friends, it also makes those on the other side redouble their efforts to oppose you. Hence Ms Johnson’s decision to join the Liberal Democrats, the better to argue for the Remain cause.

In other words, the Cummings-Johnson stagey of division and polarisation, of setting some mythical “Remain Establishment” against the “people” (in reality, only 52 per cent of the voters, at most) is not half as clever as they think it to be. If, as has been the case, it tends to unite the opposition parties in their revulsion, and to alienate MPs, activists and voters who might otherwise be inclined to support him, then it will not do much good on polling day, whenever that comes. Indeed, it makes the prospect of a Johnson deal with the EU, fanciful as it is, even less likely to pick up the necessary support in the House of Commons from Labour MPs who find the remarks about Ms Cox so unforgivably cruel.

Mr Johnson, then, can rail and goad and bait all he likes, but he is more than likely to wake up on 1 November with the UK still in the European Union and with nothing at all to show for his bluster about “do or die” and his incompetent premiership – a trail of tactical failures. His base will by then have been thoroughly demoralised and disenchanted, and the only beneficiaries of these various ploys and knavish tricks when the election comes will be Nigel Farage and, indeed, Jo Swinson, Nicola Sturgeon and, a little, Jeremy Corbyn.

The self-Trumpification of Mr Johnson makes Britain ashamed to have him as its leader. He is an embarrassment not because he is a jolly clown but because he is a sinister one, like his model in Washington. That is something of a first.

The prime minister enjoys tight 24/7 security behind a wall of armed police. Not everyone has that assured level of safety. Mr Johnson should also acknowledge that there are some crazed individuals out there who respond to such an atmosphere, and who will happily make it their business to attack MPs, judges, party workers or anyone else they perceive as “traitors”. If only for that reason, Mr Johnson should stop with the insults before it is too late.