Theresa May’s calls for the country to come together over Brexit have at last been heeded. A new YouGov poll shows the extent to which the country is now united over Brexit: 73 per cent of us think it's going badly. 85 per cent of Remainers and 71 per cent of Leavers think the Brexit talks are in a mess.

One of the 71 per cent is Boris Johnson, whose private remarks at a Conservative Way Forward dinner have been obtained by BuzzFeed's Alex Spence and Lucy Fisher over at the Times.

Johnson ranged widely and indiscreetly over the whole of British foreign policy, opining on Donald Trump, relations with China and what to do about Vladimir Putin. For the most part, while his remarks aren't helpful to see in print next to the name of the Foreign Secretary, they aren't new.

More substantial are his complaints about Brexit, and his warning that it is in danger of not being “the one we want”, but instead becoming a Brexit in which the United Kingdom remains within the European Union's regulatory and customs orbit.

And he’s right, of course. Yesterday saw the publication of the government’s draft proposal for customs post-Brexit. There is a lot of technical detail but the only section that really matters is the following:

“In determining the future customs relationship with the EU, the UK has been clear on the need to protect the Belfast (Good Friday) Agreement in all its parts, including that there will be no hard border between Northern Ireland and Ireland, and no physical infrastructure or related checks and controls. Upholding these commitments requires a joint solution on both customs, which is addressed in this paper, and an approach on regulatory standards, which will also need to be addressed.”

In plain English: the United Kingdom has committed to no border infrastructure on the island of Ireland, which means regulatory and customs alignment. It means a Brexit that keeps the United Kingdom close to the European Union on a suite of issues and severely limits the United Kingdom's post-Brexit freedom of action.

But that was clear the moment that Vote Leave – not the government, nor pesky Remainers, nor the European Union; but Vote Leave – said that after Brexit the Irish border would be as “free-flowing as it is is today”, and used the then secretary of state for Northern Ireland, Theresa Villiers, to do so.

There are a number of objections you can raise to Johnson’s contention that the Irish border is a small issue, a tail that is wagging the dog in his charming phrase. But at least it comes close to acknowledging the real trade-off, which is that either you decide the Irish settlement is worth preserving in its current form or you decide that regulatory freedom after Brexit comes first.

But Brexiteers have never taken that seriously, just as in the main most Brexiteers at Westminster and in the press have never taken Brexit seriously. Yesterday's back-and-forth about the border fallback and the need for it to be time-limited is a case in point: a fallback is, by definition, not time-limited but limited only by the question of when the fallback is no longer necessary. If you are renting a home after selling one to buy another, you don't bind yourself to ending your tenancy by a random date, but by the one on which you are able to move into your new home. The Brexiteer objection is just not serious.

And to be bought off by a guarantee that the government “expects” the fallback to end no later than 2021 is not serious either. I expect my train to work to arrive at the advertised time, but it doesn't mean it will happen.

Then you have the continual calling to “plan for no deal”, with no engagement as to what that would even mean – no panic over the compulsory purchases nor the increased Whitehall head count necessary to make it work, and so on. The reason why Brexit is not working is that the Brexit elite are not serious. They have never taken the process seriously and have never seriously tried to make Brexit work. And if they want to blame someone for the way Brexit is working out, they need to look not to Downing Street, nor Remainers, nor the EU27; but to a mirror.