Anyone who has followed the row over the Northern Irish Protocol for the past several years surely cannot help but be deeply wary of any suggestion that the Government might be actually about to do something about it.

For than once, Whitehall sources have strongly suggested that if talks hadn’t progressed by this or that date, ministers would have no choice but to trigger Article 16, only for the deadlines to come and go with no change.

A week ago, it looked as if this latest round of sabre-rustling was following a similar course.

Following an (almost-certainly hostile) leak of Liz Truss’s plans for special legislation to override the Protocol, Brandon Lewis seemed to pour cold water on the idea when he ruled it out of the Queen’s Speech. And indeed, no such Bill appeared therein.

But days afterwards, the Government has marched itself much further up the hill than ever before. The Daily Telegraph reports that Truss has set a deadline not weeks or months away, but of just 72 hours.

And today Suella Braverman, the Attorney General, has apparently received legal advice to the effect that it would be legal for the Government to overrule parts of the Protocol.

This is probably less seismic than it might sound, not least because, in the British system, Parliament can already legislate to whatever effect it pleases, so long as the Bill is properly drafted. Although this can be more or less in line with our international commitments, those do not trump its sovereign law-making power.

But more seriously because the main barriers to this course of action aren’t legal, but practical and diplomatic. A Bill of the sort apparently being drawn up by the Foreign Office would provide a locus for opposition in the House of Commons and likely provoke retaliation from Brussels. And a trade war would do nothing to ease the cost-of-living crisis.

This is the case even if, as has been suggested to me, the form of the legislation would not be to directly set aside aspects of the Protocol but to empower the Secretary of State to do so, basically creating a sounder legal footing for future carefully-targeted interventions such as the Government’s unilateral extension of grace periods.

(It is worth remembering that all the current problems with the Protocol are those arising whilst the United Kingdom is quietly refusing to implement significant parts of it. It would otherwise be even worse.)

Does the Government have sufficient will for this fight? It certainly seems to have got its allies in the press on board: “let’s destroy the myth that the EU’s priority in Northern Ireland is peace”, says this morning’s Sun.

But it is still far from clear that sufficient preparatory work has been done, either to ready the economy for the impact of a ‘trade war’ with the EU.

Nor to make the case for London’s (legitimate) interpretation of the Belfast Agreement, which does not mandate an invisible border on the island of Ireland but does guarantee Northern Ireland’s constitutional status, which certainly changed when key provisions of the Act of Union guaranteeing unfettered commerce were overridden by the legislation enacting the Protocol.

Still, there are reasons why the Government might think this strategy might work. The EU has not proven entirely unwilling to alter its rules in relation to the Protocol, and did so to resolve the row over medicines.

And having operated the grace periods for so long, London can reasonably ask Brussels where the evidence is for the dangerous distortions of the Single Market which allegedly loomed if British sausages were allowed to flow freely into Northern Ireland. They have been so flowing for two years. Where is the damage?

It is telling that in all the acres of coverage about the consequences of Truss’s plan, nobody seems to be suggesting that Ireland would be forced out of the Single Market. Yet if the EU truly believed the Protocol was necessary to safeguard its economy, and that London was prepared to tear it up, that would surely be on the cards.

Regardless, we will apparently know in less than a week whether or not the Government is serious this time. A 72-hour deadline doesn’t leave you with many places to hide.