Theresa May has ruled out allowing Nicola Sturgeon to hold a second referendum on Scottish independence in 2018-19.
The prime minister said today “now is not the time” for another vote, putting the UK government on a collision course with the administration in Edinburgh.
Sturgeon said it was “undemocratic” for May to block a referendum.
On Monday, Scotland’s first minister announced she planned to attempt to trigger a second referendum on the break-up of the UK before the Brexit process is complete.
Sturgeon will ask the Scottish Parliament to approve her plan next week. But the Scottish government must win the approval of the House of Commons and House of Lords for it to go ahead.
Speaking to ITV, May said “all our energies should be focused on our negotiations with the European Union about our future relationship”.
She continued: “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.”
Pressed on when the time would be right for another independence referendum, May repeated that “now is not the time”.
The SNP leader has said there would be a “furious reaction” in Scotland if Westminster blocked a second referendum.
Sturgeon has said she wanted the vote to be held between Autumn 2018 and Spring 2019.
She said the Brexit vote meant there had been a “material change or circumstances” which justified a second vote so soon after the 2014 referendum.
Sturgeon responded to May on Thursday by saying she was not proposing to hold a referendum “now”, but instead when “the terms of Brexit are clear and before it is too late to choose an alternative path”
She wrote on Twitter: “A Section 30 order [the law granting Sturgeon the power to call a referendum] must be discussed and agreed now to enable that timescale.
“If the Tories refuse to do so, they would effectively be blocking Scotland’s right to choose when the Brexit [are] terms clear.
“This would be undemocratic given the Scottish Government’s clear mandate and also proof positive that the Tories fear the verdict of the Scottish people.”
In her TV interview, May said the union between England, Scotland, Wales and Northern Ireland was “very precious”.
“We’ve been joined together for over 300 years. We’ve had a great history together - I believe we have a great future together,” she said.
“Together, we should put our energies into making sure we get the right deal for Scotland and for the whole of the UK.”