But senior Scottish Tory strategists are concerned that Mr Johnson clinging on to power will lead to a large spike in support for independence and reopen the debate about breaking away from the UK party.
Mr Ross, the Moray MP, has submitted a letter to the 1922 Committee calling for a vote of no confidence in Mr Johnson after the pair held a heated telephone conversation on Wednesday afternoon.
But Mr Rees-Mogg told BBC’s Newsnight on Wednesday: “Douglas Ross has always been quite a lightweight figure.”
He refused to back down yesterday and accused Mr Ross of disloyalty to the Prime Minister, saying: “If you take the King’s shilling you are beholden to the crown.”
Jamie Greene, the Scottish Tories’ Shadow Justice Secretary at Holyrood, said the comments were “completely unnecessary” and Mr Rees-Mogg “should go and have a long lie down, maybe not in the House of Commons”.
Another Tory MSP said: “To say what he said is bonkers. It is an absolute gift to our opponents, although one that’s somewhat diluted because it was Jacob Rees-Mogg who said it, who they spend their time mocking and deriding as a caricature and an irrelevance.”
‘Utter contempt for Scotland’
Entering the Holyrood chamber ahead of yesterday’s First Minister’s Questions, Mr Ross said: “Jacob Rees-Mogg, as anyone, is entitled to their opinions. I don’t have to agree with them.”
Ms Sturgeon told the Holyrood chamber she had “big political differences with Douglas Ross but even I am not as derogatory about him as his own Tory colleagues are being.”
Referring to Mr Rees-Mogg’s ‘lightweight’ comment, she said: ‘These might be personal insults directed at the leader of the Scottish Conservatives but actually they say something much deeper about the Westminster establishment’s utter contempt for Scotland.
“If they can’t show even basic respect for their own colleagues, what chance do the rest of us have?”
Mr Jack yesterday said Mr Ross was “far from a lightweight” and a “very serious politician” as he disclosed he had unsuccessfully tried to persuade the Scottish Tory leader to hold off calling for the Prime Minister to quit until the Sue Gray inquiry was completed.
The Dumfries and Galloway MP, who gave his “100 per cent” backing to the Prime Minister, said he hoped Tory MSPs would “reconsider their position” after reading the findings.