Boris Johnson has refused to grant the Scottish Government power to hold a second independence referendum.
In a letter to Nicola Sturgeon, the embattled Prime Minister said he “could not agree” now was the time for indyref2 to take place.
The First Minister previously announced plans for Scotland to head to the polls on October 19 next year to decide whether to remain part of the United Kingdom.
Sturgeon said if a transfer of power was not granted by Downing Street, the 2024 general election would act as a “de facto” referendum on the issue.
Posting her reaction to the letter on Twitter, the FM said the memo potentially represented one of Johnson’s final acts as PM and assured voters they would have their vote on Scotland’s future in at least one form.
In the letter, the PM claimed he had time to “carefully consider” the arguments for and against the vote, but cited “unprecedented challenges at home and abroad” in his rejection.
He added the 2014 devolution vote – in which Scotland backed remaining in the UK by a margin of 55% to 45 – meant a new poll was outwith “shared priorities”.
He wrote: “I cannot agree that now is the time to return to a question which was clearly answered by the people of Scotland in 2014.
“Our shared priorities must be to respond to effectively to the global cost of living challenge, to support our NHS and public services as they recover from the huge disruption of the Covid-19 pandemic and to play a leading part in the response to Russian aggression in Ukraine.
“These are common challenges across the United Kingdom which deserve our full attention.”
He continued: “On all fronts, we stand to achieve so much more for the people we serve by continuing to work together as partners.”
Johnson also thanked Sturgeon for Scotland’s response to conflict in Ukraine through the contribution of £65m to support Ukrainian troops with military hardware.
It comes just 24 hours after Scotland’s top law official admitted she “did not have the necessary degree of confidence” a vote on independence from the UK can be held as planned next year.
The FM asked Lord Advocate Dorothy Bain to refer the bill to lawmakers in London to determine whether the legal framework exists for a vote to take place.
In a ruling published on Tuesday, Bain said the Scottish Government may not have the necessary powers to legislate on the vote under the terms of the Scotland Act 1998.
She added any referendum poll would not be “legally binding” and would simply serve as an indication of public feeling towards the issue.
In a tweet, Nicola Sturgeon suggested Boris Johnson’s letter was one of his last acts as Prime Minister.
She said: “Just received this from Johnson (one of his last acts as PM?). To be clear, Scotland will have the opportunity to choose independence – I hope in a referendum on 19 October 2023 but, if not, through a general election.
“Scottish democracy will not be a prisoner of this or any PM.”
Labour meanwhile argued governments on both sides of the border were “letting down the people of Scotland.
Constitution spokesperson Sarah Boyack said: “Boris Johnson and Nicola Sturgeon are two sides of the same coin.
“Neither the Tories nor the SNP are focused on tackling the cost of living crisis or rebuilding our services from the pandemic, and both are damaging the future of devolution.”
Scottish Greens MSP Gillian Mackay said the letter came as “yet another slap in the face to the people of Scotland, who have repeatedly sent pro-independence majorities to Holyrood and Westminster”.
“The people will not continue to be held hostage by the most unpopular Prime Minister in history,” she said.
“We will ensure that Scotland’s future is placed firmly in the hands of the people who live here.”