NICOLA Sturgeon's route map to Indyref2 came after years of rancorous debate inside the SNP about what to do should the UK Government continue to oppose a new vote.

Her announcement to Holyrood last week came after she had consistently argued against an alternative "Plan B" and underlined her commitment to the path which preceded the 2014 vote.

This process involved her predecessor Alex Salmond and the former Prime Minister David Cameron agreeing that powers be transferred from Westminster to Holyrood under a Section 30 order of the Scotland Act to hold an agreed referendum.

She made clear in her statement on Tuesday she still hopes Boris Johnson may yet give his consent, making the request once more.

But with the PM adamant he won't give it amid a continuing impasse, the First Minister has become a late convert to Plan B - and even unveiled a further fall back.

Regardless or not of getting Mr Johnson's agreement, she now plans to hold the referendum on 19 October 2023 using Holyrood legislation should it be approved by the Supreme Court as within the Scottish Parliament's powers.

If the judges rule it's not competent the vote won't go ahead then and instead the Scottish Government will campaign on the single issue of whether Scotland should be an independent country at the next general election - using that event as a "de facto referendum on independence".

So that's the route map. What then are the risks for Ms Sturgeon and can the strategy work?

The first danger is that the Supreme Court is unlikely to find in her favour so she may end up disappointing her supporters many of whom are convinced the vote is definitely happening next autumn.

However, this risk has to be balanced against that of simply sticking with Plan A and facing increased discontent inside the SNP. Many members believe she has acted too cautiously in advancing the independence cause hence a rebellion in 2020 which saw a slate of critics voted onto the party's national executive committee and loyalists voted off.

So in terms of party management the risk of the FM doing nothing outweighs that of the court saying no.

And should the court not find in her favour she's already made clear she will be pinning blame on Westminster’s Scotland Act and fault will not lie with the judges or her government.

But the next risk she faces is bigger.

The First Minister has set a target for the SNP to win more than 50 per cent of the total number of votes cast at the next general election, probably in 2024, and that's a huge challenge.

In May 2015 her party won 56 out of 59 seats - a remarkable result – winning 50 per cent of the vote, meaning even this victory would have fallen short of the new GE target.

However, there is a chance the SNP could achieve such as result if events unfold in the right direction for the FM and the SNP, which they could well do.

This would see Boris Johnson remain as Tory leader or be succeeded by another populist.

Experts are already forecasting the Conservatives will mount an election bid to take the UK out of the Trade and Co-operation agreement stuck with the EU - meaning a no deal Brexit.

The extreme Eurosceptic faction inside the Tories - the European Research Group - has seen its influence increase in the aftermath of the PM's troubles. Many in the camp are highly critical of the Brexit deal and believe the UK is still too closely tied to the EU. They want a much more distant relationship.

Catherine Barnard, professor of European law at Cambridge University, told MSPs in May she believes the Conservatives will make a commitment in their general election manifesto to leave the TCA.

What this may means for GE2024 is that voters in Scotland may face a decision between opting for a no deal Brexit under Johnson or an independent Scotland in Europe.

That's certainly how the SNP will frame the choice. Polling in 2019 suggested 59 per of Scots would be more likely to vote for independence when faced with the prospect of a no deal Brexit.

The big question of course then would be if the SNP are successful is winning more than 50 per cent of the votes, would the UK Government negotiate independence terms or finally grant the FM's longed for Section 30 order?

Cabinet ministers Michael Gove and Alister Jack have both said a new vote could be held if there was ongoing support for one. Mr Jack suggested this could mean a sustained 60 per cent backing in opinion polls for indyref2.

The SNP will certainly do their best to force UK ministers to concede. If so, the First Minister will then get the Section 30 and can hold a new "gold standard" second independence referendum, the event she always wanted.