IN a few weeks’ time, possibly even in a few days’ time, lawyers north and south of the border could be dusting down their legal tomes as Nicola Sturgeon triggers the court battle ahead over Scotland’s and, by extension, Britain’s constitutional future.

Last week, a rather large rock was thrown into the pool of politics when Daren Fitzhenry, Scotland’s Information Commissioner, ruled the Scottish Government should publish its legal advice on Indyref2.

Officials had previously refused to do so, claiming it would breach professional confidentiality.

However, after an appeal, Fitzhenry ruled that publication of the legal advice would "significantly enhance public debate".

One can only imagine the dent in the ceiling caused in Bute House when the FM heard about the commissioner’s intervention.

Earlier this week, Sturgeon was on the airwaves, batting back questions about the development and, when pressed on why she couldn’t just be open and publish the advice, replied forcefully: “The ministerial code says I’m not allowed to.”

Indeed, she is right; on one level. The code clearly states ministers “must not divulge either who provided the[legal] advice or its contents”.

However, on another level there is an important caveat: they can do so “in exceptional circumstances”.

In December 2018 during Westminster’s Brexit psychodrama, it was MPs who judged the circumstances to be exceptional, forcing the then PM Theresa May to reveal her Government’s advice on Britain’s withdrawal from the EU, called for by, among others, the SNP.

Then, the Nationalists accepted the nature of the non-disclosure convention but equally accepted, given the constitutional importance of the matter at hand, the exceptional circumstances.

The same could be reasonably argued about an issue that could lead to the end of the 315-year-old Union and, ipso facto, the break up of Britain. The Scottish Government is mulling over whether to challenge Fitzhenry’s ruling in court. It has until June 10 to decide to do so or publish the legal advice. The long grass beckons.

During her media cross-examination, it was suggested that, given civil servants were now working on an independence prospectus, it was logical to assume the lawyers’ advice was that embarking on the road to Indyref2 was perfectly legal.

While Sturgeon again emphasised her desire not to breach the ministerial code, she also stressed her Government would “always act legally and lawfully”. Which indirectly answered the question.

She declared: “I only want a referendum that is capable of delivering independence, which means it has to be legal, it has to be constitutional and it has to lead to a majority of people in Scotland voting for independence.”

The FM went on to say the future of Scotland was “ultimately…for people in Scotland to decide”.

But when it was put to her that, legally, it was for Westminster to decide because it had the constitutional power over the staging of referendums, she replied: “That’s never been tested in court, of course.”

Given Boris Johnson has made repeatedly clear he would not facilitate Indyref2, the time to bring on the lawyers may soon be upon us after the SNP chief restated her desire to hold another vote by December 2023.

Intriguingly, when the previous condition of waiting until the pandemic was over was put to her, Sturgeon responded by saying Covid was now in a “new phase”.

And while the likes of Alex Salmond, Joanna Cherry and Kevin Pringle and, according to a poll this week, a majority of the Scottish public, believe the FM’s timetable is looking decidedly unlikely, the first citizen is religiously sticking to it.

If, in her heart of hearts, Sturgeon knows she would ultimately lose a legal battle, then she would be using the court process simply for political theatre; to underpin her argument that democracy should trump UK law and, in so doing, bolster Nationalist ire. Surely, the FM wouldn’t be so cynical as to do that, would she?

While the FM’s political argument will be the people have spoken on Indyref2 by voting, by a majority, to fill Holyrood with pro-independence members, Johnson’s counter-argument will be: the law is on his side.

Namely, that the devolved settlement is set within a limiting legal framework.

According to the 1998 Scotland Act, a law passed by MSPs is beyond their competence if it “relates to reserved matters,” which include those relating to the constitution, most notably, “the Union of the Kingdoms of Scotland and England”.

One suggestion has been that all referendums are advisory unless the establishing Act specifically states otherwise. In other words, a poll is merely the test of an opinion. But, of course, it would not be difficult to foresee the outrage if, say, Scotland voted Yes in a future poll but Westminster turned round and said: “No.”

Ahead of the 2014 vote I experienced one of my more memorable jaw-dropping moments. Over lunch, a senior UK Cabinet minister, in all seriousness, told me that even if Scots voted Yes, it didn’t necessarily mean independence would follow because of the complexities of the negotiations that would ensue.

The next day’s Herald front-page headline was along the lines of “Yes could mean No”. Which doubtless caused another dent in the Bute House ceiling.

Last October, the SNP administration lost a battle at the UK Supreme Court, which ruled that some provisions in Holyrood Bills about children's rights and local government were outwith the Scottish Parliament’s legislative competence.

It appeared to have serious implications for Indyref2 because the judges ruled how parts of those two Bills were fundamentally at odds with the Scotland Act as they could impinge on Westminster’s sovereignty by limiting its ability to make laws for Scotland in all areas, including devolved ones.

The Supreme Court was making clear MPs could not be constrained.

However, one academic noted if the justices in the highest court ruled against the lawfulness of the IndyRef2 Bill, it would tell Scotland the Union was a “prison based on legal coercion…which no democratic key can unlock”. That’s the constraining limit of devolution.

Fasten your seat belts.