IF the first casualty of war is truth then the impending Brexit “Sausage War” has been under way for a long time.

Five years ago, as the EU referendum campaign entered its final phase, Michael Gove argued in a BBC Scotland interview that immigration rules would be “for Scotland to decide” if the UK left the EU. This assertion – later described as a “fib and a half” by Nicola Sturgeon – was backed up by former Labour MP and Scottish Vote Leave campaign chief Tom Harris who immediately tried to explain to the First Minister how Scotland could “have a greater degree of control over immigration policy” after Brexit.

In fact, we have lost the great benefit of freedom of movement and gained nothing but a harsh, restrictive and internationally despised immigration regime which impoverishes us all.

Other utterly empty promises were made, too. The Scottish Parliament would “regain control over fishing, agriculture and important social and environmental areas” according to an official “Leave” leaflet widely distributed in June 2016 , giving Holyrood “even more power to deliver for the Scottish people.”

In fact the Scottish Parliament has been severely undermined and that process continues under a Tory hard-right government implacably hostile to the sharing of power.

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I attended every meeting of the Joint Ministerial Committee on European Negotiations and at each, without fail, some Tory Minister would claim that Brexit was bound to be wonderful for “every part of the UK “ (a patently untrue mantra particularly dear to the Secretary of State Against Scotland) though when pressed on the specifics, answer always came there none. All that rhetoric was, and is, as deceitfully empty as that emptiest of slogans “Brexit means Brexit” which I actually heard Teresa May say in the Cabinet Room of 10 Downing Street. In fact, the collective inability of the entire UK Government to actually name – at any stage over the past five years – let alone start to deliver concrete advantages from Brexit remains stark.

Yet the deception continues.

This very week, International Trade Secretary Liz Truss – once a Remainer who two days before the EU vote tweeted that the Leave campaign “could not name one country we would get a better trade deal with if we left the EU” – claimed in her new incarnation as the Boudicca of Global Britain (but hey, a job is a job) that the SNP would wilfully deny Scottish businesses the opportunity to secure what she alleged were the “benefits” of an Australian trade deal, though in reality such a deal would severely damage Scottish agriculture.

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But the prize for the most outrageous recent contribution to this blizzard of a snow job must go to “Lord” Frost (above), never elected to so much as the committee of a bowling club but now the Cabinet Minister charged with bringing home the British Brexit bacon.

“Lord” Frost, or his deputy Lindsay Appleby (now promoted to be the UK Head of Mission in Brussels), were regulars at JMC meetings. They would confidently answer every question by attempting to show how resolute and reasonable they were in contrast to the malevolent dimwits in the EU who were still failing to appreciate the UK’s iron determination to take back control of everything including the progressive march of history.

Their negotiating failures are therefore no surprise, given their extraordinary and badly misplaced self-satisfaction. Nor is their unwillingness to acknowledge those mistakes and hence the use of the word “underestimated” by Frost to describe what he thinks has gone wrong with the Northern Ireland Protocol. In fact, the only thing he estimated wrongly was his own ability.

But there is another reason for this failure which brings the deliberate dishonesty of the Leave campaign back centre stage. It is now very clear that whatever was negotiated there was never any intention by the UK Government to treat it as final. “Getting Brexit done” was a political slogan, designed only to win an election. Once that election was in the bag, the Tories always intended to be as difficult about the treaty as they could, pushing its boundaries, rejecting EU understanding of its interpretation and seeking to square Tory assertions about “no barriers in the Irish Sea” with the reality of a land border with the EU by rejecting or denying what had been explicitly agreed.

That land border need not be a trading barrier if there is a mutual respect for regulations and standards. That would be the sensible way to proceed as the EU has repeatedly demonstrated, most recently with its proposals on veterinary inspections.

But the ideological detestation (it is not too strong a word) that Brexiteers have for any EU rules have always meant that such a compromise could never happen.

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So Johnson and Gove will go on with this sleekit approach, using Frost and Appleby as their front men, in order to secure the continuing support of the hard-liners in Northern Ireland as well as their own ones at home, and by so doing retaining power and the ability to use it to whatever ends they wish which is the real purpose of Brexit.

A happy ending is hard to see. The EU will not blink but maybe perpetual irritation would serve the Tory purpose well, giving an economic enemy against which to publicly chafe as things go from bad to worse, even though the destructive nature of this low-level regulatory conflict would be horrendous for Northern Ireland and the wider island.

The only ray of hope amid this gloom may be that the international community led by a US president with roots in Ireland could make a difference by challenging the lies that have been inherent in the Brexit project all along.

That might lead to a break in the logjam, though it will be opposed by the new DUP leadership for whom the issue is the Union and their political survival, not trade. But it won’t solve the problem for Scotland. That needs independent membership of the EU.