Analysis: the second independence referendum

But she also knew what to do if Leave won and Scotland backed Remain - seize the day.

Anticipating disarray in both the Conservatives and Labour ranks, she planned a press conference at Bute House to lay claim to a second independence referendum.

The stark divergence between the Scottish and UK results made the case for her.

Scotland had voted overwhelmingly to remain in Europe and taking it out regardless was “democratically unacceptable”, she said.

This was the “significant and material change in circumstances” since 2014 that the SNP manifesto specified as the basis for Holyrood having the right to call a fresh vote.

The asteroid had struck, and Indyref2 was therefore “very much on the table”.

But will it happen?

Ever cautious, and with the public mood in flux and a thicket of problems ahead over the currency, economy and borders, Sturgeon stopped short of saying it was inevitable. Rather it was a “highly likely” option to protect Scotland’s place in Europe.

The timing is not to her liking. She would much rather be in control of events, instead of reacting to them.

But Brexit is so momentous that resistance is futile.

Yesterday Sturgeon announced an advisory panel would consider "all options", although as the EU deals in member states, not junior or associate members, its conclusion is almost certain to be that only an independent Scotland stands a chance of holding on to its current rights.

The clamour inside the SNP to hold another referendum will also propel her onward.

The SNP conference in October is likely to be one long foot-stomping demand for action.

So another referendum is not just on the table, it is very much on the cards.

As in the last parliament, a legally watertight vote requires Westminster to grant Holyrood the relevant power through a so-called Section 30 order.

In theory, Westminster could refuse. But it is hard to see how a Brexit Prime Minister like Boris Johnson, who championed “independence day” for the UK, and described the EU referendum as a triumph in democracy, could forbid Scotland from determining its own destiny.

If he did, it would mean a constitutional crisis and a stand-off between Edinburgh and London.

Sturgeon would use that all-yellow map of Scotland voting Remain to beat him into submission.

It comes as no shock that Scottish Labour should now looks towards supporting the First Minister on the issue.

Many in Labour will wonder if the party, already on the skids, could afford to be on the wrong side of the electorate yet again if there is popular support for a second referendum.

Backing - or at least not objecting - to one would not commit Labour to supporting something they don't believe in, but it would stop it looking as dogmatic as it did in 2014.

However while some Labour figures, such as former First Minister Henry McLeish, may well approve, others, notably Gordon Brown, are likely to demand an inflexible Unionist line.

Equally fascinating is how the Tories play Indyref2. Ruth Davidson is boxed in.

She led to the Tories to their best result at Holyrood last month on a pledge to resist a second referendum. There is no option for her but to defend the Union tooth and nail.

But the next Tory Prime Minister may feel more squeamish.

The memory of David Cameron resigning after losing a referendum would weigh heavily on their mind. Would the next PM want to suffer the same fate within two years of taking office?

Surely it would be wiser to hang back and outsource the fight to Davidson?

That could lead No voters to reflect if the Union still had meaning.

The ramifications of Brexit will be many, complex and unpredictable.

Amid the spinning plates, Sturgeon has the chance to be the voice of authority and stability.

If she succeeds, the sense of unity and national purpose she will be able to bring to Indyref2 makes that elusive Yes vote “highly likely”.