Nicola Sturgeon has laid down the gauntlet to Theresa May to give Scots a “real choice” and allow a second independence referendum before the UK leaves the European Union.
In a huge political gamble, the timing of which took the Tories by surprise, the First Minister announced that she will seek the approval of the Scottish Parliament next week to start negotiations with the UK Government on staging another vote.
She argued that the vote must take place between autumn next year and spring 2019 so that Scots know the outline of the UK’s Brexit divorce deal but before it actually leaves the EU.
Ms Sturgeon said this would allow Scotland to indicate to the EU before Brexit that it wants a “different relationship” than the rest of the UK, thereby helping it gain speedier entry.
A UK Government spokesman said another referendum “would be divisive and cause huge economic uncertainty at the worst possible time.” However, he did not unequivocally reject the request.
In a major blow to the First Minister, the European Commission made clear that a separate Scotland would have to apply from scratch for membership. This means it would be outside both the UK and the EU for an indeterminate period.
Ruth Davidson, the Scottish Conservative leader, said Ms Sturgeon was being “utterly irresponsible” and “has today given up acting as First Minister for all of Scotland.”
The First Minister's denials that she had been planning a second independence referendum, regardless of the UK Government's stance, were undermined by the Nationalists launching a website to coincide with her speech. It included a video from Ms Sturgeon and a fundraising target of £1 million within 100 days.
She made the announcement only hours after another poll showed a majority of Scots did not want another referendum before Brexit takes place in March 2019.
The timing of the announcement today - which was revealed by The Telegraph on Monday morning - came just 24 hours before Theresa May, the Prime Minister, is expected to trigger the start of the process of leaving the EU.
Since the UK vote to leave the European Union, Ms Sturgeon has repeatedly said a second independence referendum is "highly likely".
Scots voted 62 per cent to 38 per cent to remain the EU while the UK as a whole voted to leave.
The SNP's manifesto for last year's Holyrood election states that the party will seek a second referendum if there is a "significant material change" in Scotland's position at the time of the last referendum in 2014, such as "Scotland being taken out of the EU against our will".
However , the First Minister also promised at the time that she would not hold another referendum unless support for independence increased significantly. This has not happened.
Speaking at a specially-arranged press conference at her Bute House official residence in Edinburgh, Ms Sturgeon accused the UK Government of "intransigence" over its refusal to agree her complex plan for Scotland to stay in the single market when the rest of the UK comes out.
The First Minister said: "I will now take the steps necessary to make sure that Scotland will have a choice at the end of this process.
"A choice of whether to follow the UK to a hard Brexit - or to become an independent country, able to secure a real partnership of equals with the rest of the UK and our own relationship with Europe."
She added: "So I can confirm today that next week I will seek the approval of the Scottish Parliament to agree with the UK government the details of a Section 30 order - the procedure that will enable the Scottish Parliament to legislate for an independence referendum."
Ms Sturgeon argued that the Scottish Parliament - which has a nationalist majority when SNP and Green MSPs are combined - must have control over the referendum's timing.
She said that autumn next year would be the earliest "appropriate" time as only then will be the shape of the Brexit deal be known, but she also argued that a second independence referendum could not be held long after the UK leaves the EU in March 2019.
"If the UK leaves the EU without Scotland indicating beforehand - or at least within a short time after it - that we want a different relationship, we could face a lengthy period outside not just the EU but also the single market. That could make the task of negotiating a different future much more difficult," she said.
"These considerations lead me to the conclusion that if Scotland is to have a real choice - when the terms of Brexit are known, but before it is too late to choose our own course - then that choice must be offered between the autumn of next year, 2018, and the spring of 2019."
Asked what recourse she would have if Mrs May refused to allow a referendum before Brexit, Ms Sturgeon said: "Having sunk the ship with the Brexit vote, that would be puncturing Scotland's lifeboat as well and I don't think that would be acceptable."
Ms Sturgeon denied she had been planning a second referendum all along, having ordered her official to draw up legislation for another vote only hours after the Brexit result became known on June 24 last year.
Instead, she argued that Mrs May had forced her into calling another independence vote by refusing to agree to her "compromise" plan for Scotland to stay in the single market. This would have involved devolving all powers except defence and the macro-economy.
The First Minister was clearly annoyed that she has not been told when Article 50 will be triggered, which showed the sort of relationship Scotland had with Westminster.
She said: "I don't know whether Article 50 is going to be triggered tomorrow, or Wednesday, or next week, or the week after that."
Ms Sturgeon rejected accusations she is failing to respect the result of the 2014 referendum, which the Unionists won by a margin of 55 per cent to 45 per cent, arguing there may have been a "different decision" if voters had known about Brexit. She added: "What is at stake is the kind of country we will become."
Amid fierce criticism of the honesty of the case the Nationalists presented in 2014, when she predicted a second oil boom, she promised that Scots would get an informed debate. However, she refused to answer specific questions about the currency or how Scotland's mammoth deficit would be dealt with.
A UK Government spokesman said: “ As the Prime Minister has set out, the UK Government seeks a future partnership with the EU that works for the whole of the United Kingdom. The UK Government will negotiate that agreement, but we will do so taking into account the interests of all of the nations of the UK.
"We have been working closely with all the devolved administrations - listening to their proposals, and recognising the many areas of common ground, including workers’ rights, the status of EU citizens living in the UK and our security from crime and terrorism.
“Only a little over two years ago people in Scotland voted decisively to remain part of our United Kingdom in a referendum which the Scottish Government defined as a ‘once in a generation’ vote.
"The evidence clearly shows that a majority of people in Scotland do not want a second independence referendum.
"Another referendum would be divisive and cause huge economic uncertainty at the worst possible time. The Scottish Government should focus on delivering good government and public services for the people in Scotland.”
Ms Davidson said: "Nicola Sturgeon promised the 2014 referendum would be 'once in a generation'.
“Today she has ignored the majority in Scotland who do not want a referendum and has decided instead to double down on division and uncertainty. The First Minister's proposal offers Scotland the worst of all worlds.
"Her timetable would force people to vote blind on the biggest political decision a country could face. This is utterly irresponsible and has been taken by the First Minister purely for partisan political reasons."
The European Commission indicated an independent Scotland would have to apply to join the EU, rather than automatically being a member. Commission spokesman Margaritis Schinas said the "Barroso doctrine" continued to apply.
Former commission president Jose Manuel Barroso set out the legal view that if one part of an EU country became an independent state it would have to apply for EU membership.
At a briefing in Brussels, Mr Schinas said: "The commission does not comment on issues that pertain to the internal legal and constitutional order of our member states." But he added: "The Barroso doctrine, would that apply? Yes that would apply, obviously."
Kezia Dugdale, the Scottish Labour leader, said: "Scotland is already divided enough. We do not want to be divided again, but that is exactly what another independence referendum would do. Two years ago, 85 per cent of Scotland’s voters took part in the independence referendum and the result was a clear vote to remain in the UK.
“With our country facing all of the uncertainty around the Tories' reckless plans for a hard Brexit, the last thing we need is even more uncertainty and division. A clear majority of the people of Scotland voted to reject the SNP’s false hope and lies, and backed working together with the other nations of the UK."
Willie Rennie, the Scottish Liberal Democrat leader, said: "The SNP have been working towards this announcement for months. They have been determined to contrive a way to ignore their promise that 2014 was ‘once in a generation’."
Business leaders reacted with caution to the announcement, with the UK's internal market worth four times as much to Scottish companies than the EU.
Andy Willox, the Scottish policy convener of the Federation of Small Businesses, said: "FSB survey work conducted after last year’s Scottish Parliament elections, but before the poll on Europe, revealed very little appetite amongst smaller firms for another independence referendum."
Paul Johnson, director of the Institute for Fiscal Studies, said public spending was more than £1,000 higher per person in Scotland than in the rest of the UK, despite tax revenue being similar.
He added that the fall in the price of oil had made Scotland's financial position more difficult since the independence referendum in 2014.
Brexit had made the situation more complicated because if Scotland was inside the European Union single market and the rest of the UK was outside, trade with its largest partner could suffer.
Setting out why spending cuts or tax hikes may be required, Mr Johnson said: "Scotland looks very much like the rest of the UK in terms of its income per head, so we get just about as much tax per person from everyone in Scotland as we do in the rest of the UK.
"But spending in Scotland is more than £1,000 per person higher than spending in the rest of the UK.
"So what that means is that there is a big transfer of money from the rest of the UK to Scotland and, obviously, if Scotland were to become independent it would have to either reduce its spending by more than £1,000 per head or increase its taxes by more than £1,000 per head."
The question of whether Scotland would be able to continue to use sterling was one of the major economic arguments during the 2014 referendum - and the UK's departure from the EU could make that more unlikely.
He said: "It would clearly be more difficult to maintain the pound if the UK was outside the EU and Scotland was inside and the pressure on Scotland politically from the rest of the EU to join the euro would be significant.
"But in the end that would be a political, as much as an economic, choice."
Mr Johnson told BBC Radio 4's World At One: "Two things have changed since the last Scottish referendum. The first is that the Scottish fiscal situation has got worse, relative to that of the rest of the UK, because the oil price has gone down.
"And with spending per head more than £1,000 more in Scotland than it is in the rest of the UK that creates quite a significant fiscal problem going forward.
"Secondly, of course, the Brexit vote means that the UK looks like it is going to come out of the single market but if an independent Scotland were to be in the EU - within the single market - and the rest of the UK were to be out of it, then that helps Scotland in terms of its access to the rest of the European economies but potentially hinders it very badly in terms of its access to the UK market, depending on the political and economic agreement that was come to."