AS she returns to Bute House after a long day, how does Nicola Sturgeon feel? Does she kick off her LK Bennett heels and turn on Coronation Street, or stand at the window, G&T in hand, reflecting on the historic figures who have lived in Charlotte Square, and the difficult choices they must all have had to make? This pukka quarter has been home to brilliant lawyers, such as the memoirist Lord Cockburn, and soldiers, like Earl Haig, and millionaire merchants, like William Fettes. It has also housed an astonishing number of world-famous surgeons and physicians, and it is with them that perhaps Ms Sturgeon can best be compared. While they tended to the well-being of the local populace, she is in charge of the constitutional health of the entire nation, not just today but for centuries to come. It is, a grave responsibility, such as few in this neck of the woods have ever shouldered.

In the overheated environs of Holyrood, which is to gossip what a greenhouse is to tomatoes, it has become accepted that Ms Sturgeon will soon call for a second independence referendum. Many pundits predict it will happen later this month, at the SNP party conference in Aberdeen.

With each new shake of Brexit’s tail, Scotland’s position in post-EU Britain grows weaker and the arguments for independence seemingly stronger. The First Minister’s rhetoric repeatedly hints that a new vote will soon be called. There’s no need to rehearse in detail the stations of the cross which have thus far been passed on this pilgrimage, from Scotland’s pro-Europe vote last June, our ignored plea to be allowed to continue in the single market and, most recently, the prospect of devolved powers being returned to us from Brussels in a greatly diminished, broken state, like crockery in a house removal which was not properly wrapped.

The pressure on her predecessor Alex Salmond, which was severe, was as nothing to what Ms Sturgeon must now handle. Whatever side of the debate you favour, nobody doubts the outcome of a second referendum will be decisive. Should it be another No, as seems entirely possible, then the prospect of independence will have been quashed for an exceedingly long time. For, if Scotland upholds the Union under the present parlous circumstances, what on earth will it take to persuade naysayers to change their minds? Should the majority opt yet again for the status quo, its effect on the SNP and, more immediately, the First Minister, is the stuff of sleepless nights, and not only for her. Thanks to its general competence in government, the SNP has created a paradox: many who do not wish to separate from the UK still want it to run the country. Just as some nationalists voted for Brexit despite the party’s strong European line, those who voted the SNP into power cannot automatically be assumed to be Yes supporters.

There is worse, too, as the Cabinet knows all too well. While this is potentially the most promising of times for the SNP, it is conceivably also the most perilous. What greater spur for another referendum, you might ask, than the cavalier treatment meted out by Westminster to Scotland – and the other devolved nations – in the wake of the Brexit result? Add to this the contribution of patronising opportunists such as Ruth Davidson, who treats the SNP like rowdy teenagers needing to be taught a lesson, and a Yes seems almost assured. Referring to the repatriation of devolved powers, Ms Davidson spoke insultingly of the “mature conversation” required with Westminster before the areas we currently control are allowed back into our hands. If she had talked about grounding Ms Sturgeon until she had revised properly for her Highers, her tone could not have been more schoolmarmish.

All this, you could argue, creates a natural momentum, an unstoppable propulsion, towards a second independence referendum. The First Minister’s inner circle is no doubt gauging the mood daily, dipping the thermometer into the saucepan to see if it has reached boiling point. Among die-hard independence supporters it is probably roiling away nicely, producing clouds of steam with each new Tory and EU pronouncement. Doubtless, too, Ms Sturgeon’s team is feverishly trying to find answers to the vexed questions on the currency and economy that tripped the campaign up in 2014. But while they are preparing for battle, a poll that suggests two-thirds of us do not want another referendum any time soon chimes with most people I’ve unscientifically vox popped. Horror at being taken into Brexit has given way to fatigue. Staunch Yes voters admit not having the energy to go through it again. One even said she was going to vote No next time, because the prospect of international fragmentation with Brexit is so scary, she cannot consider further splintering.

Thus the conditions that might appear to favour a landslide Yes are not as simple as they first seem. A period of uncertainty such as the one we’re in at present cuts two ways: either convincing people to opt for self-determination, or deepening the anxiety of heading into the unknown. In circumstances like these, battening down the hatches might be more appealing to many than casting off on our own.

You can almost feel the tension blistering the black paint on the door of Bute House. Sturgeon stands poised, as if balancing the scales of justice. On one side she has the fortunes of the country, more than half of which previously rejected independence. On the other are the nationalist principles of the party she leads. The two might balance each other out to a smaller or greater extent, depending on one’s view, but it is she who must weigh the enormous risk of taking the country into another referendum which, if lost, would see her obliged to resign, and the country, and her party, severely destabilised.

If she does not seize this chance, however, will there ever be a more opportune moment? Surely it’s better to take a leap of faith now, than wait until things are calmer and clearer, by which time it will be harder to whip up enthusiasm? This is where an imagination, so often a handicap, becomes an asset. No one need worry that the reasons for independence will vanish this year, or next, or whenever Brexit is done and dusted. In the thick of turmoil, it is always hard to be patient and take the long view. Yet if you consider how many years we have waited since 1707, are a handful more really too much to ask?