Boris Johnson has denied “fuelling” the break up the UK after reportedly saying Scottish devolution was a “disaster”.
Sir Keir Starmer – who shares the PM’s opposition to Scottish independence – seized on the alleged comments at Prime Minister’s Questions.
“The single biggest threat to the future of the United Kingdom is the prime minister every time he opens his mouth,” the Labour leader told MPs.
The PM is said to have made the remarks in a call with Tory MPs on Monday.
He told them devolution – setting up separate Parliaments in Scotland, Wales and Northern Ireland – was “a disaster north of the border” and “Tony Blair’s biggest mistake”.
Sir Keir described devolution as “one of the proudest achievements of the last Labour government”.
He said the PM’s alleged remarks were not an “isolated incident” and accused him of “seriously undermining the fabric of the UK”.
“Does he agree that we need greater devolution across the UK?” asked the Labour leader.
The prime minister said devolution was a “sound policy”, which he himself had benefited from as mayor of London, but the SNP had turned it in to “a mission to break up the UK”.
“That, in my view, would be a disaster,” he added.
He was then told off by Commons Speaker Sir Lindsay Hoyle for referring to the SNP as the “Scottish Nationalist Party”.
Sir Lindsay said: “Can I just say it’s the Scottish National Party, not the nationalist party.”
Mr Johnson replied: “Mr Speaker, I’m so sorry. They’re national but not nationalist. I see, right.”
The SNP’s Westminster leader Ian Blackford said the prime minister’s “attack on devolution” was “not just a slip of the tongue, it was a slip of the Tory mask”.
“The fact is Scotland has been completely ignored by Westminster. We now face an extreme Brexit, a power grab and another round of Tory cuts all being imposed against our will by a Tory government that we didn’t vote for.”
The prime minister told Mr Blackford he was “totally wrong” and “what the UK does as a whole is far, far bigger, better and more important than what we can do as individual nations and regions,” such as the furlough scheme and coronavirus testing.
He said he wished the Scottish government would “focus on the real priorities of the people of Scotland”, such as health and education.