NICOLA Sturgeon and other political leaders have wished Ruth Davidson well after her resignation as Scottish Tory leader while highlighting her political rift with Boris Johnson.

Ms Davidson formally resigned with immediate effect this morning after making up her mind in private three months ago.

She said leading her party for eight years had damaged personal relationships and she viewed more election campaigning with a young son with “dread”.

During her leadership, the Scottish Tories overtook Labour to become the main opposition at Holyrood, and doubled their MSP and councillor numbers.

After 16 years with one MP north of the border, the party returned 13 in 2017, enabling Theresa May to staying in power with the support of the DUP’s ten MPs.

READ MORE: Ruth Davidson quits citing family pressures and election 'dread' 

The 40-year-old, who intends to stay on as MSP for Edinburgh Central until 2021, had her first child, Finn, with her partner Jen Wilson last October.

Ms Davidson said she stood behind Boris Johnson - provided he was trying to get a deal on Brexit.

On Twitter, the First Minister said: “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.”

But she later told the BBC: “I think there are political factors in her decision as well.

"It’s been an open secret she’s has had many and deep disagreements with Boris Johnson and the direction he’s taken the Conservative party and indeed in the UK in.

“And I guess that does beg a question - if the Scottish Tory leader can’t reconcile herself to this Prime Minister and what he wants to do for the country, then why should the rest of Scotland have to do?”

In a statement, Mr Johnson said: “On behalf of everyone in the Conservative and Unionist Party, I want to thank Ruth for her wonderful service over the last eight years.

“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.

“I wish Ruth, Jen and Finn all the best for the future.

Mrs May said she was sorry to see Ms Davidson step down.

“Thank you for all you've done for our party and our Union over the last 8 years, and enjoy your well-deserved family time with Jen and Finn,” she tweeted.

UK LibDem leader Jo Swinson said she had always admired Ms Davidson’s “kick-ass approach” to politics.

She said: “Our politics are different Ruth, but I have always admired your kick-ass approach, breaking glass ceilings and challenging the old guard. Wishing you & Jen all the best - enjoy all those magical moments with baby Finn.”

Scottish Labour leader Richard Leonard said: "There is no doubt that Ruth Davidson has been responsible for the increase in support for her party in Scotland and her departure as Leader will be a massive setback for them.

“However, the timing can be no coincidence and shows clearly that Boris Johnson's conduct as Prime Minister isn't acceptable even to those who share his politics.

“I wish Ruth and her family all the best for the future.”

Scottish Secretary Alister Jack said, who was one of the 13 Scottish Tory MPs elected in 2017, said: “Ruth Davidson has been an outstanding leader of the Scottish Conservatives for nearly eight years and I want to put on record my thanks for everything she has achieved.

“She has inspired a new generation of Scottish Conservative politicians, activists and supporters - and in turn that has transformed our party’s fortunes.

"At the heart of Ruth’s success has been her brilliance as a communicator and her passion for strengthening Scotland’s place in the UK.

“She has consistently articulated a positive vision of the Union and that is why she played such an important role in the successful 2014 campaign to stay part of the UK and why a majority of Scots continue to oppose a second independence referendum."

Scottish LibDem leader Willie Rennie, who worked with Ms Davidson on Better Together in 2014 only to see her say his party couldn’t be trusted in the Union, added: “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.

“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 cavalier approach to running our country. Liberal Democrats will speak for those people.”

MP Nick Boles, who left the Conservative Party in April this year, tweeted: "The only person who could have tempted me to return to the Conservative fold is Ruth Davidson.

"Her characteristically honourable and human decision removes the last significant voice of liberal, progressive conservatism from the party."

Tory MSP Adam Tomkins said: “Ruth has been my boss for the past three years, but first and foremost she is my friend. She was the reason I joined the Tory party and why a lot of people voted Tory. But she is absolutely right to put family first. The toll that political leadership takes on family life is extraordinary.”