ASKED on the BBC’s Andrew Marr show about an independence referendum if the UK Government takes Scotland out of the single market, Nicola Sturgeon replied: “Don’t think I’m bluffing.” Within hours, Theresa May appeared to promise to do exactly that.

The Prime Minister has been widely criticised for failing to set her negotiating objectives after Article 50 is triggered. But she has now stated them with disarming clarity. There will be no attempts to keep “bits” of the EU, said Mrs May, when repeatedly questioned on Sky about whether membership of the single market remained an option: no obligations will be accepted that require Britain to answer to any existing EU institution.

There will be no free movement, no accepting the rulings of the European Court of Justice, no attempt to remain a member any of the multiple, overlapping EU-sponsored free trading zones: a customs union, single market or the European Economic Area. Also, there will be no Norway, Turkish or Swiss options. This was not so much a pick-and-mix Europe but a no-trace-of Europe.

The SNP’s more confident supporters will welcome the new clarity from the Prime Minister. Some were distinctly uneasy at the First Minister’s offer, only last Friday, to shelve independence indefinitely if Scotland was allowed to remain in the single market. Surely freedom is more important than a trade deal? The 45ers in the SNP say the First Minister should, paraphrasing Shakespeare’s Lady Macbeth, screw her courage to the sticking place.

But yesterday Ms Sturgeon ruled out a referendum this year, no doubt to prevent the issue dominating the May local elections when the SNP hopes for big gains. She insists no one had been talking about holding a referendum in 2017 but many in her party were hoping at least for a firm commitment pre-2018. This may not be a failure of will on her part but it suggests that the consultation on the draft independence Bill, which closes tomorrow, has not registered an overwhelming clamour for an early referendum.

Ms Sturgeon may not want an early referendum either but the Brexit cliff edge is looming and time is not on her side. If Scotland is to remain in the single market, it really needs to become independent before Britain leaves in 2019. It will be much more difficult to rejoin the EU thereafter from outside. Also, there will be a new UK single market that will lock Scotland into a new and tighter UK Union.

The last independence referendum took two years to organise from the date of the Edinburgh Agreement in 2012. Legislation will be needed and there will be a fight with Westminster about Holyrood’s right to hold another referendum.

The Green Party has indicated that it supports independence if the alternative is hard Brexit, so that should give the First Minister the majority she needs for the independence Bill in Holyrood. But there could still be some negotiating there.

What are the chances of a Yes vote? The conventional wisdom is that Scots are fed up with referendums and too confused to think of independence. However, the polls show that 45 per cent still favour Yes.

Since most are relatively young, SNP strategists believe they could supply the energy to persuade the “five per centers” to vote Yes. Many of the 2014 Yes groups have been spontaneously kicking off again in the past six months.

The Labour party in Scotland is an empty shell, split on the constitution and in no position to lead a No campaign. The Tories are compromised because Ruth Davidson was a Remainer and can be presented as a puppet of right-wing UK Tories. The Liberal Democrats no longer matter. Many in the SNP believe the press has been overwhelmed by social media, where independence voices are much stronger and where the anti-establishment tide is still running strong.

Attitudes may also harden among swithering No voters as the reality of hard Brexit emerges. Mrs May is expected to push for sectors of UK industry, such as Nissan, to be given privileged access to EU markets. The City of London may have a special deal on migration. This will be a brutal rebuff to the First Minister’s plea that Holyrood should have powers over immigration and its own privileged access to the single market.

Unless Mrs May comes up with a convincing package of greater powers for Holyrood that compensate for exclusion from the single market, Ms Sturgeon may have no alternative but to double down and go for a second independence referendum; that is, if she still has the bottle.