IN one sense, there was no surprise in Nicola Sturgeon’s rapturously received pledge to pave the way for a second independence referendum at the SNP’s conference in Glasgow.

Ms Sturgeon said little she has not already said or suggested in the immediate aftermath of the vote to leave the EU. Also, this was not a pledge to hold a referendum. It was the announcement of a consultation on plans for a bill to allow a referendum. Nevertheless, could the SNP leader be painting herself into something of a corner?

Her conference opening speech contained messages for her party, for the UK Prime Minister and for the wider public. Many in the SNP feel Brexit has changed everything and demand a second, prompt vote on independence. Yet the polls suggest that the SNP has been denied the Brexit bounce it hoped would bolster support for independence. But many feel Alex Salmond is right and that support can increase, as in the 2014 referendum campaign, aided this time by the argument that Scotland needs a continuing relationship with Europe and the best way to achieve that is never to leave.

That would entail a gamble, of course, and there were caveats in Ms Sturgeon’s speech about a referendum taking place if needed to protect Scotland’s interests. She told the conference: “Whatever I choose, I’m sure you will back me.” But that may be optimistic. The faithful might see it as a promise of a referendum soon. Polling might tell a different story; that a Yes vote might not win. Also, we remain in the dark about Brexit. Foreign Secretary Boris Johnson added, typically, to the fug of obfuscation yesterday by insisting that the concept of a European single market (to which Theresa May is keen to retain access) was increasingly useless.

The First Minister will be heartened that trusted ally Angus Robertson won the election for deputy leader so emphatically. Had his nearest rival Tommy Sheppard done so, the pressure would have been greater still as he wants to start the ball rolling on a second referendum. Notably, Mr Robertson did little to rein in the enthusiasm of the conference audience, declaring that “We are very, very close to independence”. The SNP has pledged to have two million doorstep conversations about independence. Now we are to have a referendum bill. If the party leadership intended to manage expectations, it is managing them in one direction.

The message to Mrs May was quite different. Demands for rejection of a hard Brexit, and new powers over international deals, immigration, fisheries and farming saw Ms Sturgeon adopting an aggressive stance. It is traditional to be polarised at the outset of negotiations but she has certainly put her cards on the table.

Yet the UK Government might feel it has little incentive to listen to a party with independence as its reason for being. In addition, Ms Sturgeon implies she will walk away from the negotiating table if talks falter, opening her up to accusations of acting prematurely.

The First Minister appears to believe Mrs May will be persuaded to allow a referendum, necessary for any result to be binding. Is this likely? The UK Government is unlikely to want Scotland to become like Catalonia; opting for separation by a majority of votes whose validity is rejected.

To the wider public, particularly to previous No voters, Ms Sturgeon’s appeal is more complicated. She seeks to appear reasonable and still to wish to strike a positive Brexit deal. Yet we seem to be moving inexorably closer to a second independence referendum. Could it be won? There are too many imponderables at present to know. We still know little, of course, of what Brexit will ultimately mean. Scrutiny of a deal is denied by the democratic deficit of blocking MPs a vote on the terms. Ms Sturgeon could not be clearer that Scotland will not be denied its say and a second referendum seems increasingly to be the vehicle.

But timing is everything and many of the economic questions that troubled voters in 2014 remain unanswered. It is a sign of political and economic turbulence that the dynamic about the euro has changed. Two years ago, the question was whether an independent Scotland would be forced to use the currency. But the euro now looks more stable than the pound. Also in 2014, there was heated debate about whether an independent Scotland would be allowed to remain in Europe. Now, leaving the UK is seen as our route to safeguarding EU status.

At present, Ms Sturgeon appears to be pinning the case for independence on a linked animus to the Conservative Government and Brexit. But bigger questions will have to be addressed at some point. Ms Sturgeon has a delicate balancing act to manage, knowing that a wrongly timed referendum could end her career and set the party’s cause back by decades. This cannot be allowed to distract the First Minister and her colleagues from governing the country. That is what they were elected to do.