DOUGLAS Ross has performed a “humiliating climbdown” over his demand for Boris Johnson to resign and cannot “credibly remain in post”, according to the SNP .

Only a month after the ­Scottish Tory leader insisted Johnson must quit over the Downing Street ­Partygate scandal, it has emerged the Prime Minister has been invited to address the Scottish Conservative conference next month.

Johnson is also planning to ­visit Scotland this week as he faces ­questions from police investigating ­alleged lockdown breaches, but it is not expected he will be joined by Ross on the trip.

The Scottish Conservatives are holding their conference in Aberdeen on March 18 and 19, at the same time as the UK spring conference in Blackpool, meaning Johnson may address the Scottish gathering virtually.

READ MORE: Boris Johnson to come to Scotland next week – but Douglas Ross won't join him

A Scottish Conservatives spokesman said: “The Prime Minister will be invited to address the party ­conference, just as has been the case in any other year.”

SNP MP Pete Wishart said it was a “humiliating climbdown for ­Douglas Ross” which “demonstrates that the Scottish Tory party is nothing more than a branch office under the ­control of Tory HQ in Westminster”.

“Such an embarrassing U-turn leaves Mr Ross with egg all over his face – and will do little to counter claims by senior Tories that he is a ‘lightweight’ whose authority is ­crumbling,” he said.

“It simply isn’t credible for the Scottish Tories to demand Boris Johnson’s resignation one week, then invite him to give a keynote speech the next.

“This will only add to speculation that the Scottish Tory Leader is on his way out the door. They can’t both credibly remain in post.”

Ross was among the Tory MPs who wrote to the 1922 Committee chairman Sir Graham Brady seeking to trigger a no-confidence vote.

In an interview on January 12, after Johnson admitted attending a ­Downing Street party in May 2020, the Scottish Tory leader said: “I said yesterday if the Prime Minister ­attended this gathering, party, event, in Downing Street on May 20, then he could not continue as Prime Minister. So regretfully, I have to say his position is no longer tenable.”

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He was backed by more than a dozen of his own MSPs in a move branded as a “revolt” against the Prime Minister. Then leader of the house Jacob Rees-Mogg then dismissed Ross as a “lightweight”, further fuelling tensions between the UK and Scottish parties. It had been reported Johnson would be “banned” from ­attending the Scottish Tory party conference following the war of words.

On Friday, Downing Street confirmed that Johnson had received a legal questionnaire from Met officers investigating events in No 10. He now has seven days to adequately explain his attendance or face a fine for breaking his own Covid rules, and is reported to have lined up a legal expert on coronavirus regulations to help him defend his participation in the parties. However, he is scheduled to leave Westminster this week to go round the UK, insisting he is “getting on with the job”.

No 10 said he will start the week with a visit to a manufacturing site in Scotland, before heading to an oncology centre tackling coronavirus backlogs in the North West of England.

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THE Prime Minister said: “I’m getting out of London this week and taking a simple message with me – this Government is getting on with the job of uniting and levelling up the country.

“Access to good healthcare, a good education, skilled work, reliable transport – none of this should depend on where you live. We’re changing the rules of the game to put fairness back at the heart of the system and focusing on the priorities that ­really matter to people. This is our mission and we’re getting on with ­delivering it.”

Senior Scottish Tories have ­attempted to downplay the significance of Johnson not meeting with Ross during the visit, with one source saying: “When the Prime Minister has come to Scotland before there have been times when Douglas has been there and there have been times where Douglas hasn’t been there.”

So far, 15 Tory MPs have publicly called for Johnson to quit, while ­others are thought to have privately written to the 1922 Committee ­calling for a no-confidence vote.