Leave our shores and Brexit appears even more hopelessly strange – and the people perpetrating it even more peculiar – than they do when you are at home. In Asia, where I have spent the past week, figures such as Boris Johnson and Jacob Rees-Mogg are seen as curiosities with views that are openly risible. Of course it’s stupid to leave the world’s biggest trading bloc and make your now lonely future dependent upon the kindness of unforgiving strangers. Can’t they see that?

No country has ever done what Britain is attempting because it is so obviously crazed. Trade agreements are a carefully balanced mutual opening of partners’ markets with a hard-to-work-through calculus of gains and losses that takes years – even decades – to negotiate. Brexiters promised that Britain would be different and that unravelling a 45-year-old web of deep relationships would be quick and effortless, with Britain “holding all the cards”. All palpably false.

Do they understand, asks anyone familiar with Asia, how merciless the Chinese and Japanese are in pursuing their own interests, how carefully they size up who has power and to what degree? How can a credo so plainly delusional seize hold of so many people?

Just take an issue such as aviation safety, very live in Asia after the two Boeing 737 Max 8 crashes. The US Federal Aviation Authority subcontracted substantial parts of the evaluation of the plane’s safety to Boeing itself. How crucial it is now that there is Airbus and the European Union’s Civil Aviation Safety Agency as alternatives.

Indonesia has just cancelled all its Boeing 737 Max orders because there has been an irreparable breakdown in trust between it, the company and the US government. Why do British Brexiters, such as Johnson, not see this, but seek instead to swap the influence that Britain has in Europe for becoming a satrapy of the protectionist, self-interested, even dangerous United States? And why are they so little challenged by the British media and the British political opposition?

These conspire to create a moment of perfect crassness in which there is every chance Britain could leave with no deal

You have to explain that Brexit is the expression of a malaise that is now accelerating the dynamics of economic and political decline. The Conservative party stands at the centre, but the roll call of culprits extends to the Labour party’s factionalism; Britain’s overwhelmingly rightwing media, which act as propagandists for Toryism and Brexit; our class system, in which plummy accents are seen as evidence not of potential bird-brains but, rather, “natural” authority; our unbroken faith in British exceptionalism; and our connivance in mind-boggling social inequalities. All of these now conspire to create a moment of perfect crassness in which there is every chance Britain could leave the EU with no deal in three weeks’ time.

Former attorney general Dominic Grieve’s wrenching admission that he is ashamed of his party is further evidence that its thinking adherents now acknowledge its dysfuctionality. Toryism is a unique amalgam of a social movement, obsessed with sustaining privileges, and a political party. It possesses all the social signifiers of status, including received pronunciation and public-school entitlement, particularly important in England’s counties and small towns, and it has the capacity to transmute that standing into political office.

Traditionally, the party’s tools have been pragmatic ones such as the willingness to do whatever works, but only to ensure that the same sort of people occupy as many formal and informal positions of power as possible, from the lord lieutenants in the counties to those running quangos.

Anglicanism once gave moral spine to this English nomenklatura: most bishops were Tories, along with judges and newspaper editors. To be Tory was a badge of one’s soundness and social acceptability. The first-past-the-post voting system and a fiercely partisan press sealed the deal. To be a Tory was to exemplify the top of England, which is why its leaders consistently put party unity before loyalty to country. In their mind, it is one and the same.

Mrs May magnified her problems by her ineptitude: but any Tory leader would have faced the same impossible forces

This whole edifice is being undermined by two big trends: the transformation of Thatcherism into an unthinking religion conflating total fealty to markets with English nationalism; and Conservatism’s new secularism, which eschews even kindly Anglican morality and concern for the disadvantaged. It is becoming a vengeful English national party whose strategic goal is the blind assertion of sovereignty in order to build an English Thatcherite utopia. Hence Johnson, although a dishonest and feckless chump, is the frontrunner to succeed Theresa May; hence also the implacable resistance of the European Research Group to any kind of reason. Mrs May magnified her problems by her ineptitude, but any Tory leader would have faced the same impossible forces.

The Labour party has never thought through how to beat the destructive forces that it confronts, even as they implode. Tony Blair chose to connive in them, resulting in them eating him; Jeremy Corbyn imagines they can be beaten by turning Labour into a socialist sect, but one whose narrowness of reach and appeal will never allow him to build the necessary broad coalition to assault the Tory citadels. Meanwhile, the millions facing stagnating living standards and diminishing opportunity are ever easier prey to the appeals of English nationalism. Foreigners and the dastardly EU are to blame for all our ills – we must stand up to the “humiliations” of the “bullying” EU.

Thus we are where we are. I returned early from Asia to march yesterday with my fellow countrymen and women who see this clearly. We want to remain in the EU as the best deal possible, confirmed by a second referendum, but we also understand the profundity of the economic, constitutional and social reforms necessary to make membership sustainable. The English settlement has to change. Above all, we see that Toryism and Labour are broken as parties, causes of, not solutions to, the current emergency. Whatever happens next, we are just at the beginning of many convulsions.

The old order has been shattered. Time to fight for the new order.

• Will Hutton is an Observer columnist