Most other countries have spend decades forging trading links and concluding a vast network of informal and formal trade agreements. We will be tearing ours it. For the UK, it is year zero.

As the the inevitable presence of a hard border, this much the House of Commons Brexit Committee seemed at last to recognise in its report published on Friday. But, contrary to any sense or experience, Downing Street remains adamant that there can be no "hard border". This has become an unvarying mantra that has long since lost touch with the real world.

Yet, if Theresa May had understood the rules of the system that we have been part of for 44 years, Booker writes, she would know that we will be compelled to apply our own border controls in Northern Ireland, just as we do now on all goods from third countries as members of the EU.

Without such controls, we would otherwise fall foul of precisely those "WTO rules" our "hard Brexiteers"- the "Ultras" as we call them - are so fond of. These are the rules which prohibit discrimination in trading arrangements that favour one country over others.

If we were to exempt goods entering Northern Ireland from border controls, every other country in the world could claim the same rights. So now there is talk of leaving Northern Ireland in the EU customs union and the Single Market, to move the inevitable hard border into the middle of the Irish Sea.

At that point, step forward those Democratic Unionist MPs, on whose votes Theresa May's fate depends, to say that although they also cannot accept a hard border with the south, this compromise is even more unacceptable. It would be the first step towards a united Ireland.

Once again, Booker thus observes, those "muddy fields" and "dreary steeples" re-emerge at the centre of UK politics. Yet the tragic fact is that this crisis was wholly avoidable.

Like so many other problems we have brought on ourselves in the shambles we are making of Brexit, this one would never have arisen if only Mrs May had not made that reckless decision last January to leave the wider EEA, allowing us to leave the EU but without any "hard borders".

But, instead of looking forward to a measured transition from full membership of the EU to a stable trading partnership, we are haunted by May's idiosyncratic – even dictatorial – approach to governance, relying wholly on advice from Nick Timothy. We enter this new and critical phase in our history slave to a decision made by people who hadn't the first idea of its consequences.

In normal circumstances, the sustaining myth of any nation is that the people running the government actually know what they are doing. But, as government faces its most complex task since the war, we find decisions being taken not on the basis of knowledge but fuelled by the ignorance (and obstinacy) of a tiny number of people.

In this context, readers will recall that, in the recent Irish report of UK's handling of the negotiations, we had an observation from Ian Forrester - the British judge in the ECJ.

He criticised "the quality of politicians in Westminster" and said there had been "a fair amount of contact" between him and the British government on the issue. Of all those he had met, "only one person … had any real grasp of the complexities involved [in leaving the EU]".

It takes little imagination to work out who that person might have been. When I put it to Sir Ivan Rogers that he was the "mystery man", he did not disagree. He has now left government service.

Sir Ivan himself has his own views on the capability of the civil service and, in his view, the personnel and the structures have deteriorated over the period of his career. They are not, he believes, up to the task confronting the nation, any more than are the politicians.

This damages beyond repair the idea that we can rely on the people "in charge". Contrary to general expectations, the higher up the tree we go, it seems that –the less knowledgeable people are – and the more serious their errors.

And here, Booker and I are as one: that Mrs May's ill-considered decision to take the UK out of the Single Market will be looked back on as the most fateful single error in the entire dismal story of Brexit. Of all the possibilities for an ordered Brexit. there was never any rational choice other than the Efta/EEA option.

This is not just another free trade agreement, a top-level graduation of the other comprehensive deals so far concluded by the EU. The EEA, uniquely, embodies the complex mix of governing and administrative institutions and the dispute mechanisms.

These are fully integrated with the surveillance and enforcement systems, which then rely on high level consultation and communication – with the whole package bound by a common legal framework which is routinely and reliably updated to keep it in phase with the EU's Single Market acquis.

Consistently, though, we hear the prattle of ignorant minds, arguing that regulatory conformity is sufficient to ensure market access, when this is but an element of the whole. It is the complexity and sophistication of the EEA Agreement, taken as an indivisible whole – rather than any one part - which enables the near-frictionless trade which its members enjoy.

The long and the short of this is that we confront an all-or-nothing situation. We either adopt the whole package – giving us something we can build on and develop - or we are on the outside. There are no half measures. If we choose an alternative - whether a Ukraine-style deal, a CETA analogue or something similar to the agreement with the Republic of Korea - the outcome will be the same. We will be on the outside. It is just a matter of degree.

What almost everybody seems to have lost sight of is that we are currently members of the most comprehensive and sophisticated treaty organisation in the world, which in turn is host to the most heavily integrated trading system in the world. That makes the Single Market unique. There are no parallels. Thus, to withdraw is inevitably going to be traumatic. Things are not going to be the same. There was never any prospect that they could be.

Yet, time after time, we are hearing politicians and others who voice expectations of normality. To them, it is almost as if leaving the EU was of the same magnitude as changing the shop from which one gets one's papers delivered.

And, if seventeen months after the referendum – following a lacklustre campaign where the important issues were barely discussed – we still cannot get the basics right, then there seems little hope that things can improve. Like a pernicious weed which, if left neglected, will take over a garden, ignorance has taken over the debate – from the highest to the lowest level.

Remarking on this phenomenon, Pat Byrne, the founder of the Irish airline CityJet, declared: "It almost seems that the Brexit car crash must be allowed to happen before the people of the UK see the folly of it". This, could, however, he more of a case of fools rushing in.