John Swinney has said that he was "stunned" by Mr Carlaw's sudden resignation, and wished him well for the future.

The Deputy First Minister told BBC Radio Scotland: "I had absolutely no inclination this was coming.

"Leadership is tough, and his statement is very personal reflection on his own assessment of his position. I can't imagine it has been an easy conclusion for him to come to."

READ MORE: MP Douglas Ross tipped to be new Scottish Tory leader

Jackson Carlaw resigned from his role as leader of the Scottish Conservatives earlier today after less than six months in charge.

Mr Carlaw said: 

"Over the summer I have had the chance to think hard about my role as leader of the Scottish Conservatives.

"Nothing is more important to me than making the case for Scotland's place in the United Kingdom.

“I believe the Scottish Conservative and Unionist party is the most important voice in Scotland for setting out that positive argument. I am clear that nothing must get in the way of doing so.

"In the last few weeks, I have reached a simple if painful conclusion - that I am not, in the present circumstances, the person best placed to lead that case over these next vital months in Scottish politics prior to the Holyrood elections."

He added: “Given the importance I attach to the job, I've therefore decided to stand down with immediate effect.

“It is not an easy call but I have spent a lifetime in politics holding to the maxim that party and country comes first.

“I believe I am doing my duty by holding to that view now.

“I simply believe that a new leader will be able, as we recover from the Covid emergency, to make the case for the Scottish Conservatives and the Union better than me. That is all that matters.

"I leave the job with genuine pride at my time in office, both as interim leader and as leader for the last year.

“I especially enjoyed the eight years as deputy leader and being an integral part of the success achieved.

READ MORE: Jackson Carlaw: How Scotland reacted to Tory leader stepping down

“Managing the transition from Ruth Davidson's leadership to a refreshed party has been a challenging task but I feel confident that I leave the role with the party in good heart and, crucially, with time to elect a new leader so he or she can prepare for the elections next year.

"The Scottish Conservatives will fight those elections as we have always done - as the one party that will unequivocally speak up for all those Scots who do not want to go back to more division, but instead want our country to move on, as part of the United Kingdom, able to rise to the challenges of the future.

“I will fight that cause hard for these next few vital months as a loyal member of my party.”

Former Scotland Office minister Douglas Ross is being lined up to lead the Scottish Tories.

Mr Ross, 37, was the only UK minister to resign over the Dominic Cummings scandal and is understood to have the backing of Ruth Davidson and other senior party figures.