Boris Johnson has come under fire for reportedly telling a virtual meeting of Conservative MPs that devolution had been a “disaster” in Scotland.
Mr Johnson also reportedly described it as predecessor Tony Blair’s “biggest mistake”.
The SNP and Labour have both criticised Mr Johnson.
But government sources suggested the prime minister had been making “more of a reference” to the SNP’s running of Scotland than devolution in general.
Mr Johnson was in a Zoom meeting with Tory MPs representing dozens of seats in northern England on Monday when he is said to have made the remarks.
The Sun newspaper reported the PM had told the MPs “devolution has been a disaster north of the border”.
This comes six months before vital elections right across the UK, important particularly in Scotland, just when the SNP has been starting to warm up its campaign, and just when discussions about how the UK government ought to respond are taking place too.
It is one thing – and, of course, legitimate – for political rivals to criticise each other. But to suggest the way that Scotland has been run for more than a decade is a “disaster” is quite another.
And the worry among Scottish Tories is the implication that Boris Johnson’s understanding of the political situation is far from complete.
Mr Blair’s Labour government brought in devolution for Scotland in 1999, including the setting up of a parliament in Edinburgh.
A Downing Street source said: “The PM has always supported devolution, but Tony Blair failed to foresee the rise of separatists in Scotland.
“Devolution is great – but not when it’s used by separatists and nationalists to break up the UK.”
Scottish Parliament election
Former first secretary of state and Conservative MP Damian Green told BBC Newsnight that Mr Johnson “has made clear he supports devolution” and his party “accepts devolution”.
“The disaster has been that it’s being used by separatists to try and break up the United Kingdom,” he said.
Elections for the Scottish Parliament take place next May. The SNP is currently the largest party with 61 MSPs and the Conservative Party is the second-largest with 31 – eight seats ahead of Labour.
Ms Sturgeon’s SNP says a second referendum on independence – following Scotland’s vote against it in 2014 – should happen if her party wins. But Mr Johnson has ruled this out.
In response to Mr Johnson’s reported remarks to Tory MPs, Scotland’s First Minister Nicola Sturgeon tweeted: “Worth bookmarking these PM comments for the next time Tories say they’re not a threat to the powers of the Scottish Parliament – or, even more incredibly, that they support devolving more powers.”
She added that the “only way to protect and strengthen” the Scottish Parliament was through independence for Scotland.
SNP MP Philippa Whitford told BBC Newsnight Mr Johnson’s reported comment was “very odd for a prime minister who claims to be trying to hold the union together”.
“It isn’t just this flippant comment today,” she said. “It comes on the back of the internal market bill, which absolutely removes powers from Scottish Parliament.”
The bill sets out rules for the operation of the UK internal market – trade between England, Scotland, Wales and Northern Ireland – after the end of the Brexit transition period in January.
Labour’s shadow Scottish secretary Ian Murray said the reported remark “confirms Boris Johnson doesn’t believe in devolution and would put the future of the United Kingdom at risk”.
He added: “Devolution is one of Labour’s proudest achievements and we will always fight for a strong Scotland in the UK.”
But the leader of the Scottish Conservatives, Douglas Ross, tweeted: “Devolution has not been a disaster. The SNP’s non-stop obsession with another referendum – above jobs, schools and everything else – has been a disaster.”
It has been suggested by some taking part in the MPs’ Zoom meeting that Mr Johnson was answering a question that had been put to him about devolution in England.