The Prime Minister ruled out the SNP’s plan for a fresh vote in late 2018 or early 2019, claiming it would be “unfair” to ask Scots to decide their future “without the information they need” about the UK’s future relationship with Europe.
The First Minister hit back, calling Mrs May’s stance a “democratic outrage” and warning the Prime Minister she was gambling with the fate of the Union.
In a TV interview, the PM had said: “Just at this point, all our energies should be focused on our negotiations with the European Union about our future relationship.
“To be talking about an independence referendum will make it more difficult for us to be able to get the right deal for Scotland, and the right deal for the UK.
“And more than that, I think it wouldn’t be fair to the people of Scotland because they’re being asked to make a crucial decision without all the necessary information – without knowing what the future partnership would be, or what the alternative of an independent Scotland would look like.”
Mrs May added: “For that reason, I say to the SNP, now is not the time.”
The declaration came as legislation to trigger Article 50 of the Lisbon Treaty was given royal assent, clearing the way for the Prime Minister to start the formal Brexit process by her end-of-March deadline.
She will underline her opposition to a second referendum today as she unveils her “Plan for Britain”, which includes an appeal to preserve the 300- year-old Union.
“That Union is more than just a constitutional artefact,” Mrs May is expected to say. “It is a union between all of our citizens, whoever we are and wherever we’re from.
“So our Plan for Britain will put strengthening and sustaining that Union at its heart. It means taking the big decisions when they’re the right ones for Britain in the long-term. Putting the national interest above any other consideration.”
“And it means ensuring that we act in the interests of the whole country – creating jobs and supporting cities, towns and communities right across our United Kingdom.”
Holyrood ministers will push ahead with a formal request for Westminster to give the Scottish Parliament the powers needed to hold a referendum at the start of next week.
But there will be “no discussion” of the request for a Section 30 order under the Scotland Act, Downing Street confirmed, pitting the two governments against each other with the UK poised to enter complex Brexit negotiations.
Yesterday the UK government would not confirm when a vote might be allowed. Reports have speculated that approval could be withheld until the next Scottish elections or beyond, with Mrs May potentially demanding that the SNP secure a majority in 2021 before a second referendum is granted.
But a Scottish Government spokesman said Ms Sturgeon would insist a second poll takes place before the next election.
“The mandate is clear: the mandate is for the parliamentary term,” the spokesman said. “The First Minister has made clear her preferred timescale and that is the timescale we’re working to, but the mandate is the basis on which this Government was elected and the manifesto covers the parliamentary term.”
Downing Street said Mrs May made her announcement on the eve of the SNP conference in Aberdeen after Ms Sturgeon ambushed the UK Government with her call for a referendum on Monday.
Number 10 has denied that the First Minister’s surprise intervention derailed plans to trigger the formal Brexit process on Tuesday.
At a hastily arranged press conference in Edinburgh, Scottish Tory leader Ruth Davidson and Scottish Secretary David Mundell underlined the Prime Minister’s message, saying public consensus was needed before a referendum would be considered.
Mr Mundell revealed he had asked the Prime Minister to set out her stance ahead of next week’s Holyrood vote. The pair insisted that the timing was all wrong and Scots must have a chance to see how the country’s relations with the EU will develop in the years ahead after Brexit.
Mr Mundell said: “What we’re saying is that a specific proposal has been brought forward suggesting asking people to choose Scotland’s constitutional future at a time when people in Scotland could not make a fair assessment of alternatives. That request is being declined.”
Ms Davidson said: “The people of Scotland should not be subjected to another referendum until we can clearly see what the two options are ahead of them on both sides of the argument and until there is public and political consent for that to be brought forward. We know to our cost that referenda are divisive.”
Scottish Labour leader Kezia Dugdale backed the UK Government’s refusal to grant a pre-Brexit referendum, but said a vote after the UK had left the EU should be allowed if called for by the Scottish people.
“There absolutely should not be another independence referendum until after Brexit,” she said. “We have no idea what Brexit looks like, or how it will impact our economy and families in Scotland.”