Ruth Davidson has quit as Scottish Conservative leader, citing both “professional and personal” changes as reasons for her decision to step down.

Jackson Carlaw MSP has been appointed interim leader pending a leadership election, a position he held during Ms Davidson’s recent maternity leave.

Ms Davidson said leading the Tories in Holyrood – the job which she took on in November 2011 – had been the “privilege of my life”.

But as she formally resigned as leader, Ms Davidson – who had campaigned for Remain in the 2016 European referendum – cited the “conflict” she had felt over Brexit.

She clashed with Boris Johnson during the Brexit referendum, and her resignation came just a day after the Prime Minister announced he will temporarily suspend Parliament in the run-up to the UK’s EU departure date of October 31.

Mr Johnson paid tribute to her “wonderful service” to the Tories over the past eight years.

The PM said: “She has dedicated so much time and energy to the role and has been instrumental in the revival of our electoral fortunes in Scotland.

“She should take immeasurable pride in the pivotal role she played during the Scottish independence referendum campaign, where her passionate support for our Union was crucial to the result.

“I will miss the incredible leadership she has given to our party in Scotland, but I am delighted that she will continue to use her enthusiasm, passion and dedication to make the case for Scotland’s place in the United Kingdom from the backbenches and beyond.”

It is understood Ms Davidson had been thinking about her position for the last year, and spoke to her party about this at the time of the European elections in May.

She said that while “work has always come first” over the past eight years, the arrival of her son Finn last October meant she was making a “different choice”.

The “biggest change” in her life had been starting a family with her partner Jen Wilson, she added.

With elections looming, she said the prospect of “spending hundreds of hours away from my home and family now fills me with dread”.

And she added: “That is no way to lead.”

She said: “I fear that having tried to be a good leader over the years, I have proved a poor daughter, sister, partner and friend. The party and my work has always come first, often at the expense of commitments to loved ones.

“The arrival of my son means I now make a different choice.”

Ruth Davidson during a press conference in Edinburgh following her announcement
Ruth Davidson during a press conference in Edinburgh following her announcement (Jane Barlow/PA)

Campaigning in the Scottish independence referendum, where voters in 2014 opted to stay part of the UK, was “without doubt, the most important contribution of my working life”, Ms Davidson said.

And while she did not back Mr Johnson in the recent Tory leadership campaign, she made clear in her resignation letter she would “continue to support the party, the Prime Minister and Scotland’s place in the United Kingdom”.

She said she would continue to serve as MSP for Edinburgh Central until 2021, while on Brexit she said Mr Johnson had assured her – after she “stared him right in the eye” – that he wanted to reach a deal to take the UK out of the EU.

“I stand absolutely full-square behind the Prime Minister’s attempts to bring back a deal that can pass in the House of Commons,” Ms Davidson said.

She stated: “I think we had three golden opportunities to support a deal, I think that the people right now who are saying they would do anything to avoid no-deal had a goal gaping in front of them three times and they hit the ball over the bar.

“And for all the elaborate plans of bringing down governments and installing Ken Clarke and Harriet Harman as a sort of job-share prime minister, the simple way to avoid no-deal is to vote for it.”

Ms Davidson urged parliamentarians: “Please, for those people trying to avoid no-deal, make it clear now that if a deal comes back to the House of Commons, you will vote for it.”

Former prime minister Theresa May said she was “sorry” to see Ms Davidson stepping down as leader.

She tweeted: “Thank you for all you’ve done for our party and our Union over the last eight years, and enjoy your well-deserved family time with Jen and Finn.”

First Minister Nicola Sturgeon tweeted: “I wish Ruth well for the future. I know well the toll political leadership can take on family life, and no-one will grudge her more time with her young son.

“There will be opportunity later to discuss the politics of her decision – but for now, I’ll simply send my best wishes.”

Meanwhile, Scottish Liberal Democrat leader Willie Rennie said the Tories could struggle north of the border without Ms Davidson.

“There is little doubt that Ruth Davidson has brought a spark of life to the Conservatives and to Scottish, even UK politics, at a time that it really mattered,” he said.

“Often I found her fun to work with where we agreed and a formidable opponent when we didn’t. She can leave the stage in the knowledge that she played her part and played it well.”

But he added: “The Conservatives know that her absence is a problem for them as they will struggle to speak for the hundreds of thousands of people with moderate views who want Scotland in the heart of the UK and reject Boris Johnson’s cavalier approach to running our country.”