BORIS Johnson tried to persuade Douglas Ross to stay in his Government but failed, The Herald has been told, as political friends and foes praised the Scot for resigning his post and taking a "principled position" over the Cummings row.

Senior Conservatives sources said that the Prime Minister, in the wake of the Dominic Cummings press conference, had a telephone conversation with the Moray MP to try to keep him at the Scotland Office but was unsuccessful in convincing his colleague to stay on.

One  senior party insider said: “Douglas is a very single-minded individual; perhaps it’s down to him being a football referee and it’s black or white, a penalty or not a penalty. The PM spoke to him and tried to persuade him otherwise but…[did not succeed.]”

No 10 declined to comment on the phonecall. An exchange of letters between Mr Johnson and Mr Ross is due to be published this afternoon. A replacement minister could be named by this evening.

READ MORE:  Scottish MP Douglas Ross quits government over Cummings scandal

Mr Ross, 37, who had been the Parliamentary Under-Secretary of State for Scotland for just five months, said this morning he was quitting his role after hearing Mr Cummings' efforts to defend his 260-mile trip from London to Durham.

He said he could not "in good faith" tell his constituents who could not care for sick relatives or say goodbye to dying ones while obeying lockdown rules that Mr Cummings had acted appropriately.

Shortly after Mr Ross released his resignation letter to the PM on social media, the Scotland Office issued a terse statement from Alister Jack, the Scottish Secretary, who said: “I would like to thank Douglas Ross for his contribution as a minister at the Scotland Office. I know he will continue to be a dedicated and hardworking constituency MP for Moray.”

A No 10 spokesman said Mr Johnson regretted Mr Ross’s decision to quit. He said: "The Prime Minister would like to thank Douglas Ross for his service to Government and regrets his decision to stand down as Parliamentary Under Secretary of State for Scotland."

At her daily press conference in Edinburgh, Nicola Sturgeon, asked about Mr Ross’s resignation, said she suspected like the majority of the population, “he believes Dominic Cummings’ actions were not acceptable and the handling of that and the retrospective rewriting of the rules to try and somehow justify it was not acceptable either”.

The First Minister added: “He has taken the principled position of resigning from the UK Government and we’ll see whether others decide to follow suit”.

Mr Ross's Conservative colleague, the former minister Tim Loughton - who has called for Mr Cummings to quit - offered his support to the Scot, describing him as a "very principled and respected colleague".

He added: "This brave decision underlines his decency;[it] will not have been taken lightly and should not be readily dismissed."

Ian Blackford for the SNP said: "This will have been a difficult decision to make and I respect Douglas Ross for taking it. This issue transcends politics. It is about protecting trust and confidence in the public health advice. The Prime Minister must remove Dominic Cummings from his post without further delay."

Sir Ed Davey, the acting Liberal Democrat leader, tweeted: "This must have been a difficult decision for Douglas. But he's surely right.

"I hope other Conservative MPs consult their consciences, recognise what's right to restore public confidence and trust & join other Conservatives in calling for Cummings to go."

Labour's David Lammy also took to social media, saying: "Good for him. Douglas Ross has done the decent thing. Many Conservatives are just as appalled as the rest of the country by the double standards shown by this government."

READ MORE: Analysis: Douglas Ross's resignation will continue Cummings furore just when PM hoped it was easing

Mr Ross is a qualified football referee. He has officiated at domestic and international matches. He was one of the officials at the 2015 Scottish Cup Final.