Douglas Ross announced he would resign as the Scottish Conservative leader after the General Election in a bid to stop a growing internal rebellion over his decision to U-turn and stand again for Westminster.

It is understood his resignation is the first time that a UK political leader has quit during a general election campaign plunging his party and his own bid to return to the Commons into crisis.

A Tory source told The Herald Mr Ross's statement was released in a bid to put a halt to briefings being made against him by some of his MSPs.

They added that his rationale was that by announcing he would standing down after the election a line would be drawn under the matter.

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"The focus is on the election just now and Douglas leading us through the other side, that is the focus," they said.

"Part of this is to draw a line under the situation. Some of the MSPs have clearly been briefing and it's not been helpful which is why Douglas has taken this position. We are hoping that in doing this, it will stop that and get everyone focused on the election."

Mr Ross, who became Scottish Tory leader in August 2020 without a contest, had previously pledged to leave the House of Commons and focus on leading the Tories at Holyrood but prompted fury among his own MSPs by instead declaring on Thursday that he would run for the Aberdeenshire North and Moray East constituency.

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This followed the Scottish Conservative board sacking David Duguid, the incumbent candidate, who had been reselected by local party members, because of his ill health on Wednesday night.

Further pressure was heaped on Mr Ross over the weekend when concerns from within his team emerged in the Sunday Mail newspaper about previous expenses claims.

His supporters insisted that the expenses furore was not part of the reason for the resignation but the fact that such details were being leaked to the media showed his position was untenable.

Mr Ross, in a statement released yesterday, stressed he was "committed to fighting and winning the Aberdeenshire North and Moray East constituency".

He stated: "“I have served as MP, MSP and leader for over three years now and believed I could continue to do so if re-elected to Westminster, but on reflection, that is not feasible.

"Should I be given the honour to represent the people and communities of this new seat, they should know being their MP would receive my complete focus and attention.

READ MORE: As Douglas Ross quits as Tory leader, where did it all go wrong?

"I will, therefore, stand down as leader following the election on July 4, once a successor is elected."

Speaking to reporters later Mr Ross admitted the timing of his resignation was "not how I'd have envisioned it".

Asked what the reaction from his colleagues had been he said: "Many of them have not just been saying to me but to the media that they were unhappy.

"Clearly it had always been my intention to continue as an MSP up until the general election, the circumstances changed very quickly last week. There was a vacancy in a key seat which is a straight fight between the Scottish Conservatives and the SNP, I put myself forward and was selected by the local association there because I want to beat the SNP," he said.

"The timing is not how would have envisaged it but I think it's right to take these decisions and take them at the time. I've reflected over the weekend on what colleagues and others have said, I'm absolutely committed as the candidate for the Conservative & Unionist Party for Aberdeenshire North and Moray East."

Mr Ross added he will quit Holyrood if he is returned to the Commons, but will remain as an MSP if he fails in his general election bid.

He will take part in what is now expected to be a challenging debate on BBC Scotland this evening and is also expected to unveil his party's general election manifesto later this month.

Mr Ross faced a party backlash last week after he announced he would run again for Westminster with further pressure heaped on him last weekend when concerns from within his own team emerged in the Sunday Mail about previous expenses claims.

His supporters insisted that the expenses furore was not part of the reason for his resignation announcement but the fact that such details were being leaked to the media showed his position was untenable.

The process to replace Mr Ross is not expected to start until after the general election and could take months if there is a contest.

However, MSPs could rally around a single candidate in which case it is likely Mr Ross's successor would be unveiled shortly after polling day, possibly within days.

Russell Findlay, the justice spokesman, is said to have “support across the party” and will be encouraged to stand by multiple senior figures. 

Craig Hoy, the party chairman, Jamie Greene, the former justice spokesman, and Stephen Kerr, the former chief whip, who is also standing for a Westminster seat, are also seen as potential frontrunners.

Other candidates could include Murdo Fraser, the economy spokesman, Meghan Gallacher, the deputy leader, Liam Kerr, the education spokesman, and Maurice Golden, the former chief whip, although multiple MSPs said there was little desire for people to publicise their intentions before the election.

The First Minister accused Mr Ross of treating voters with contempt insisting he was "not at all surprised" that Mr Ross announced he will step down as Scottish Tory leader after next month's General Election.

But Mr Swinney claimed the Tory was behaving in a "contemptible" manner.

The First Minister and SNP leader said: "One minute he wants to come to Holyrood to become First Minister, he now seems to have given up on that by standing down from the Conservative Party leadership.

"He now wants to go to Westminster, if that doesn't work out for him he will carry on with his representation in the Scottish Parliament.

"That is a level of taking the electorate for granted which is totally unacceptable.

"And I am staggered that the Conservative Party is putting up with this because it just is demonstrating contempt for the electorate."

He went on to accuse Mr Ross of "really treating the electorate with contempt", adding: "He wants to have it on his terms.

"Well, when you're in politics, you're in it on the terms of the electorate. We all accept that. It's the electorate that decides."

Scottish Labour leader Anas Sarwar said: "Douglas Ross is the first senior Tory to fall as a result of this election campaign but I hope he's not the last and, on July 4, if people vote Scottish Labour here in Scotland and they vote Labour across the UK then we can see every senior Tory fall across the country.

"So that this incompetent, failing, lying, sleazy, right-wing Government can be booted out of office after 14 years of carnage and chaos that has negatively impacted on Scotland and negatively impacted on communities across the country."

Scottish Greens co-leader Patrick Harvie said Mr Ross running for Westminster while Mr Duguid was "still convalescing in hospital" had meant "some in the Conservative Party have finally woken up and recognised what a nasty bully Douglas Ross is and they have had enough of him".

He stated: "Douglas Ross has been perhaps the worst leader in the Scottish Tories' history and the Scottish Parliament and indeed, Scottish politics, will be well rid of him."

Alex Cole-Hamilton, the Scottish Liberal Democrat leader, said: “This is yet more proof of a Conservative party in abject disarray.”

Meanwhile, the Prime Minister insisted Mr Ross had a record to be to be proud of and said that while he had "enjoyed" working with the Scottish Tory leader, he respected his decision to step down from the post.

Rishi Sunak said he had worked with Mr Ross on issues such as "standing up to the SNP's misguided gender recognition reforms" and promoting the North Sea energy sector.

He added: "I think that's a track record that Douglas can be proud of and I've enjoyed working with him, but I respect his decision."