The thing to understand about Brexit and Remain voters is that Brexit is only part of the problem. Many Remainers cast their votes with only moderate enthusiasm. They were not motivated, most of them, by any great enthusiasm for the European project. But they took what they considered to be a prudent, pragmatic, view of the national interest. They wanted a moderate, quiet life; and the status quo, however irritating it might sometimes be, was at least a known quantity and therefore preferable to the great unknown that must be unleashed by Brexit. Remain was a proper, old-fashioned, Tory choice.

And therefore, of course, rather unfashionable. But then, as far as many Remain voters were concerned, if Boris Johnson and Nigel Farage were for Leave, then there had to be something distinctly fishy about the entire enterprise. One purported to offer starry-eyed internationalism and the other dead-eyed nativism and it was hard to see how both could have the Brexit they promised. At some level, Leavers had to sign up to Team Boris or Team Nigel.

This mixture of 'liberal Brexit' – a vision most keenly and persuasively articulated by The Spectator – and grimy 'nativist Brexit' has proved uncommonly useful to the Brexiteers. Any criticism of one can be deflected by insisting that ‘No, that’s not what Brexit means at all’. Referendums are very personal epiphanies, after all, and what you mean by, or want from, your vote is not necessarily what your neighbour, who voted the same way, wants from his or hers.

According to the Foreign Secretary, 'Brexit is not just the great liberal project of the age, but a project that over time can unite this country'. Well, it’s a nice idea and one that resonates in Old Queen Street but, no matter how much you squint at it, making Brexit a liberal project runs into the awkward fact that a) the people who voted for it are not, in the main, liberals, b) nor are the people implementing it.

Still, if you wanted to reassure Remain voters that everything is peachy, I’m not sure you would call for Boris. As he put it himself, this morning: 'I can see that in making this case now I run the risk of simply causing further irritation'. Indeed, which is one reason why if you have little to say that is useful it might be better to say nothing at all. Even if the message might be believed, the messenger will not be.

Trust is a precious commodity and some politicians don’t have it. Nor do they regain it by claiming Brexit is a glorious vote for 'self-government'. Are we to believe that France and Sweden and Germany and the Netherlands are not in some reasonable sense free countries? Apparently so. The EU is not a souped-up Ecuadorian embassy and being a member of the club is not incarceration. The ability to leave matters.

Brexiteer rhetoric is often poisonous, not least when it implies that every British government since Ted Heath’s ministry has betrayed the national interest, 'lashing' us to a European project actively hostile to British liberties. Come on.

When you start down this road you end up in the extraordinary position where the single market – arguably the only thing Britain ever truly liked about and wanted from the EU – is downgraded to 'recondite' status. Come on, with bells on.

Not that the Foreign Secretary’s contorted logic was confined to this. There was much more. Exports to non-EU countries have grown remarkably in recent years, therefore we must leave the EU to increase our exports to non-EU countries. This seems unconvincing evidence of the EU’s strangling grip on the British economy.

But it takes some chutzpah to say, in the same speech that first, 'It is only by taking back control of our laws that UK firms and entrepreneurs will have the freedom to innovate, without the risk of having to comply with some directive devised by Brussels' and then, just a few paragraphs later, 'of course we will need to comply with EU regulation in so far as we are exporting to the EU'. As cakes go, this one takes the biscuit.

The Foreign Secretary’s speech was stuffed with contradictions of this sort. He rejects the idea that Britain is a country of little significance, being nothing more than a small 'offshore island comprising fewer than one per cent of humanity'. Fair enough. Meanwhile, it 'seems extraordinary' that the UK should remain 'lashed' to 'a regional trade bloc comprising only six per cent of humanity'. Britain is big but Europe is small. This is the Father Dougal theory of foreign policy.

At last, however, we got to the nub of the matter. 'So much of this is about confidence and national self-belief,' Johnson says, evidently unaware of the manner in which he resembles nothing so much as a Dulux-dog Alex Salmond. Yet the more he sounds like the former SNP leader the more he undermines his central thesis that Brexit is a moment of internationalist liberalism, not nationalist parochialism. If we just believe in the confidence fairies hard enough, they will see us right.

Moreover, the more the Foreign Secretary boasts of British exceptionalism the less necessary Brexit seems. For if we have remained so remarkable, the impositions of EU membership cannot have amounted to much more than a very moderately-sized hill of beans. 'We already boast an amazing economy,' Johnson says, which, if true, leaves you to wonder why you’d risk entirely avoidable economic upheaval. There’s more, too: 'We are the nation that has moved the furthest up the value chain of the 21st century economy'. Again, if this means anything – which I concede it may not – it suggests Brexit is the answer to, in economic terms, a non-existent problem.

And this, in the end, cuts to the guts of the problem with the Brexit case. On the one hand you have sunny optimists such as the Foreign Secretary forever shambling around the place remarking on how wonderful everything is; and on the other you have the thunderous pessimists such as Nigel Farage darkly warning that everything is actually terrible and Brexit is the only way to rescue Britain from its otherwise dystopian future. It is the difference between Brexit sunrise and Brexit sunset; the difference between a happy and liberating option and a grim and pessimistic necessity. Britain can be brilliant or Britain can be broken.

They can’t both be right. And so the Brexiteers switch – sometimes in the same damn speech – between one channel and the other. It might be lovely if Johnson’s vision of what the journalist David Rennie has called 'Cutty Sark Britain' was the dominant force behind Brexit but, you know, I’m just not sure it is. And neither whiff-whaffing pablum, nor dubious jokes about sex tourism from our preposterous Foreign Secretary can change that.