Prime Minister Theresa May has rejected Nicola Sturgeon's call for a second referendum on Scottish independence saying "now is not the time".
The Scottish First Minister has said the she wants a new vote before a deal on Britain's withdrawal from the European Union is finalised.
However Mrs May said: "Right now we should be working together, not pulling apart.
"We should be working together to get that right deal for Scotland, that right deal for the UK as I say that's my job as Prime Minister and so for that reason I say to the SNP: now is not the time."
Speaking to ITV News's Robert Peston, Mrs May said that the focus of the entire UK should be on the forthcoming Brexit negotiations.
She said that a new vote on Scottish independence would make it more difficult to get a "good deal" with the remaining 27 member states.
"So when the SNP Government say that it's the time to start talking about a second independence referendum I say that just at this point all our energies should be focused on our negotiations with the European Union about our future relationship," she said.
"And to be talking about an independence referendum will, I think, make it more difficult for us to be able to get the right deal for Scotland, and the right deal for the UK.
"More than that I think it wouldn't be fair to the people of Scotland because they'd be asked to make a crucial decision without the necessary information without knowing what the future partnership will be or what the alternative for an independent Scotland would look like.
"So I think just now we should be putting all our energies into ensuring that we get that right deal for the UK and the right deal for Scotland in our negotiations with the European Union, that's my job as Prime Minister."
In the Commons, the SNP's Pete Wishart warned ministers that any attempt to block a referendum would simply backfire.
"Surely there can be no case for standing in the way of democracy and defying the will of the democratically elected parliament in Scotland." he said.
"If this Government are thinking for one minute of standing in the way of Scottish democracy, it will be the biggest recruiting sergeant possible for the cause of Scottish independence."
Responding to Mrs May's interview, Ms Sturgeon said she does not want a referendum now, but when the terms of Brexit are clear and "before it is too late to choose an alternative path".
On Twitter, she added: "If the Tories refuse to do so, they would effectively be blocking Scotland's right to choose when the Brexit terms (are) clear.
"This would be undemocratic given @scotgov (the Scottish Government's) clear mandate and also proof positive that the Tories fear the verdict of the Scottish people."