Her Majesty’s secretary of state for foreign and commonwealth affairs, Boris Johnson, is an accomplished confidence man. Like all conmen, he appeals to the larceny in the blood – the wish of the mark to get an impossibly good deal. Mr Johnson’s 4,000-word job application (he wants to be prime minister) in last Saturday’s Telegraph is a masterclass in doublespeak and smarm. Almost everything it says about the prospects of a deal is palpably false, but that hardly matters. It would be worrying in any other foreign secretary, but we know better than to expect this one to share the truth, even if he is in possession of it. However, it is enormously revealing about the state of opinion in the Conservative party. He smells the larceny in the party’s blood; he knows how it wants to be seduced.

The members of the Conservative party who might still make him prime minister want to believe Britain is “the second-greatest power on Earth after America”, or at least that it was that as late as “the early years of this century”.

They want to believe that wicked foreigners are taking from us £350m a week. What other explanation could there be for national relative decline? Perhaps, because they want to believe it, the more imaginative ones will go on believing, even in the teeth of the prompt, official and unequivocal denial by Sir David Norgrove, chair of the UK statistics Authority. Sir David’s unprecedented public rebuke does not only distinguish between gross and net contributions, as most criticism does: he also points out that the subsidies for agriculture and science that Mr Johnson promises will have to come out of the money simultaneously promised to the NHS.

But there are some things Mr Johnson tells his electorate which they take as self-evident. Elderly conservatives don’t have to hope to believe them. They are instinctively convinced they must be true. Chief among these is the claim that you cannot be a patriot and a lover of the European Union. The British civil servants in Brussels are praised to the extent that they sabotaged the work of everyone else there. The only sight that Mr Johnson will admit frightens him is that of “so many young people with the 12 stars lipsticked on their faces … with genuinely split allegiances”.

This is an argument that would be dismissed – quite rightly – if it were applied to Scottish supporters of the union. It is entirely possible to be a true patriot and to feel part of a wider polity than that of one’s own nation. In fact, it’s the only way to be. True patriotism demands a sense of proportion, and a loyalty to political and cultural structures wider and more generous than those of the nations that brought us two world wars.

Being frightened by the idealism and the generous impulses of young people who declare their allegiance to a European ideal is not true patriotism but the last resort of the scoundrels who inflicted on us this catastrophe. It is reminiscent of the Daily Mail’s demand before the election that Mrs May “crush the saboteurs”; and it is laying the foundations for a new legend of the stab in the back, which will be ready when the old stories about how Britain was the second greatest power in the world, bled dry by the envious leeches of Germany, lose their power to enchant.

In this new version of the myth, the humiliations and impoverishment that must follow Brexit will still be the fault of wicked foreigners, but resentment and denial of reality feed on one another, and can never be satisfied. New villains will be needed. The catastrophe will be blamed on everyone who foretold it. We have no need to accept this. The task for all those who believe that Brexit will be a disaster is first to mitigate it and second to ensure responsibility and blame are pinned to the irresponsible clique of Bullingdon boys who brought us to the cliff edge of the referendum and then pushed us off – chief among them Mr Johnson himself.