Asked by his spin doctor in 2016 how a Brexit referendum could backfire, David Cameron replied in cod-Shakespearian English: “You could unleash demons of which ye know not.” Well, ye know now.

Brexit has pushed the right into a demonic orgy. It is throwing off the standards it once pretended to abide by – parliamentary sovereignty, family values, monarchism, unionism. For all its rage, don’t underestimate how much it is enjoying the release from its taboos. The Brexiters’ bacchanal is giving Conservatives a rolling revolution, which is pushing the country into a crisis no one foresaw.

In 2014, opponents of the EU put forward a moderate programme that balanced restoring power to Westminster and protecting the economy. “We are perfectly at liberty to pursue participation in the single market without being saddled with the EU as a political project,” Owen Paterson wrote in a representative example of the propaganda of the time. Talk of compromise had vanished by 2016. Vote Leave offered no programme at all. In their complacent belief that a Remain victory was guaranteed, Cameron, parliament and the media did not insist that we must define what Brexit meant before voting on it. The referendum therefore didn’t produce a mandate but a blank cheque, which fanatics have scribbled on ever since.

Revolutions devour their children because what is radical one day in a crisis becomes a sellout the next. We forgot that Theresa May’s “red lines” delineated a hard Brexit in 2018. By 2019, her one compromise, the backstop to protect the Irish peace process, had become too much for the right to bear.

By any empirical measure the Tory party has ceased to exist. Half of its members support Nigel Farage

“At no time and in no circumstances should a communist place his personal interests first,” said Chairman Mao. In the Conservative and Unionist party, as in the Chinese Communist party, personal interests are discarded if they threaten the purity of the Brexit cause.

Not so long ago, a Conservative who had left two wives, walked out on his children and jumped into the bed of a woman almost half his age could never have been prime minister. The Tories were the party of the family and traditional values. Now they are the party of broken families and no values apart from leaving the EU.

Not so long ago, Conservatives were unionists. Now a majority of party members say they would be prepared to see an independent Scotland and united Ireland rather than stay in the EU. They add that they could also live with “significant damage” to the British economy, which reminds me that not so long ago the Conservatives were the party of business rather than the party that wants to “fuck business”.

The first Tories were defined by their willingness to defend Charles II. Now the party of throne and state is willing to provoke a constitutional crisis by ordering Elizabeth II to prorogue parliament. Since the Treaty of Rome was signed in 1957, every Tory leader from Macmillan to Cameron believed Britain must be part of the EU. Now you cannot lead the Tory party unless you believe Britain must leave the EU.

Facebook Twitter Pinterest Grant Schapps, a Johnson supporter Photograph: Neil Hall/EPA

We don’t have a revolutionary past and have no memory of how people dismissed as creepy failures by all who knew them can suddenly appear in power. That moment can’t be far off. Talentless nobodies fill the Labour frontbench. Their sole “quality” is loyalty to the leader. Meanwhile, Johnson’s likely victory is allowing sleazy losers to curry failure and follow him into power. Gavin Williamson, fired by May after a secrets leak because she had “lost confidence in his ability to serve”, Iain Duncan Smith, the architect of the cruel universal credit “reform”, and Grant Shapps, an all-but-forgotten party chairman, who used a false name to pitch schemes to get “stinking, filthy rich” to easily impressed punters, have resurrected themselves as Johnson loyalists in the expectation that their new master will reward his friends. You don’t need to ask why they are attracted to a mendacious leader or he to them.

Imagine the release ripping through a rightwing England, so often portrayed as the home of the uptight and old fashioned. Just as Jeremy Corbyn’s example gives his otherwise politically correct supporters permission to engage in antisemitism and misogyny for the good of the cause, and Trump gives evangelical Christians permission to break the Ten Commandments, so Johnson gives Conservatives permission to stop pretending they believe in family life or personal responsibility. They can let it all hang out now. Who cares about their divorces and affairs, their dirty secrets and their little swindles? Johnson’s very presence at the top of the party proves that none of that old stuff matters. Indeed, when set against the lies and betrayals of such a leader, the sins of ordinary Conservatives appear to be so small they are barely sins at all.

Play Video 1:41 Boris Johnson: I don't remember calling the French 'turds' – video

Johnson seems to be the demon that Cameron predicted would take over the British right. I can’t see him as a master villain, though. He is too fatuous to be a frightening leader, as it is far from clear whether he is leading anyone. By any empirical measure, the Tory party has ceased to exist. Half of its members support Nigel Farage, who has an effective veto over Johnson’s Brexit policy. Unless Johnson clears his actions with him, Farage can split the rightwing vote by running Brexit candidates against Conservative MPs who provoke his disapproval.

On this reading, Johnson isn’t a Mao or even a Trump or Corbyn, just straw in the wind. He has used Brexit to bring himself to power. But he’s a fool if he doesn’t know that the passions that are blowing him to Downing Street could blow him away. When I think of how his supporters will turn on him when his promises prove to be false, or of how his cocky words of June 2019 will turn to dust by October, I could almost feel sorry for the fraud. Almost.

• Nick Cohen is an Observer columnist