Boris Johnson has rejected Nicola Sturgeon’s call for Holyrood to be given the power to hold another vote on Scottish independence.
“I cannot agree to any request for a transfer of power that would lead to further independence referendums,” the prime minister said in a letter to the first minister on Tuesday.
Sturgeon said Johnson was “terrified of Scotland’s right to choose” because he believed the independence campaign would win.
In his letter to the SNP leader, Johnson said he had “carefully considered” the case she had made.
But he said both she and her predecessor Alex Salmond had made a “personal promise” that the referendum in 2014 was a “once in generation” event.
The prime minister said: “The UK Government will continue to uphold the democratic decision of the Scottish people and the promise that you made to them.
“For that reason I cannot agree to any request for a transfer of power that would lead to further independence referendums.”
Sturgeon said on Twitter: “Tories are terrified of Scotland’s right to choose - because they know that when given the choice we’ll choose independence. Tories have no positive case for the union - so all they can do is attempt to deny democracy. It will not stand.
She added the Scottish government “will set out our response and next steps before the end of this month - when we will also again ask to back Scotland’s right to choose our own future”.
Last month, Sturgeon requested powers be transferred, saying there was a “democratic case” for a second ballot to be held on the issue.