Boris Johnson suffered a double blow today as the Tories' Scottish leader officially resigned admitting 'conflict' over his plan for Brexit.
Ruth Davidson confirmed she has quit her role after eight years - just hours after Mr Johnson announced he would shut down Parliament for a month.
Ms Davidson, who had a baby last October with her partner Jen Wilson, said she was quitting for family reasons - as the idea of leaving her son Finn for an election campaign "fills me with dread".
But she also felt "conflict" over her party's hardline Brexit stance - and delivered a coded slapdown to Boris Johnson by begging politicians to "unite" the country.
It came moments after former Cabinet minister Lord Young "risks undermining the fundamental role of Parliament at a critical time in our history".
Ms Davidson told a press conference in Edinburgh: "Respect is what is missing from our debates, and without respect you cannot have understanding and you cannot unite which is what we in Scotland and in the UK need to do."
Yet Ms Davidson was careful not to fully tear into Boris Johnson - who she said she stood fully behind in efforts to get a deal with the EU.
Instead she turned her fire on MPs in the Commons - saying they must "for God's sake" back a Brexit deal if and when it comes back to Parliament.
She said: "I went down to Downing Street last week to meet him in a private meeting. I stared him right in the eye and I asked him - 'I need to know, are you actually trying to get a deal or not?'
"He categorically assured me that he was. He believes his efforts in Biarritz [at the G7] have helped open the door."
In her resignation letter, she wrote: "Inevitably, much has changed over the years of my leadership - both personally and in the wider political context.
"While I have not hidden the conflict I have felt over Brexit, I have attempted to chart a course for our party which recognises and respects the referendum result, while seeking to maximise opportunities and mitigate risks for key Scottish businesses and sectors."
Ousted Prime Minister Theresa May, who was a close ally of Ms Davidson, said: "Sorry to see Ruth Davidson step down as Leader of Scottish Tories.
"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."
First Minister of Scotland 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."
It came as the fightback against Boris Johnson with MPs vowing to rush through a bid to block the "tinpot" PM's no-deal Brexit .
Labour and other opposition MPs will force laws against no-deal through Parliament - just before Mr Johnson shuts down the Commons for a month.
And they look set to be joined by Tory Remainer rebels, who are furious at their leader's "coup" of shutting the doors from September 12 to October 14.
Tory MP Oliver Letwin said he will "certainly" back legislating next week as talks between other Conservatives reportedly went on until 2am.
Tory veteran Ken Clarke accused Boris Johnson of "blatant lies" and vowed to back legislation next week. Former Chancellor Philip Hammond added: “A number of my colleagues would have preferred to wait ... and move in late September. That will now not be possible. We will have to try to do something when parliament returns next week."
It came as protesters marched on No10 to demand an end to the coup amid and two official legal fights to block it, one of whihc is from campaigner Gina Miller.
Ms Davidson, who campaigned for Remain in the 2016 European referendum, had clashed with Mr Johnson over the issue of the UK's future membership of the EU.
The Scottish Tory - who was touted as a future leader of the UK Conservatives until she explicitly ruled out taking on the post - went up against Mr Johnson in a televised referendum debate at Wembley Stadium in 2016.
She has been a vocal critic of Mr Johnson, and during the race to succeed Theresa May Ms Davidson backed first Sajid Javid and then Jeremy Hunt over the eventual winner.
A spokesman for the Scottish Conservatives said on Wednesday: "Ruth will make her position clear in due course. There will be no further comment tonight."
However he stated: "This decision is not connected to today's Brexit developments in any way."
Ms Davidson , who is engaged to partner Jen Wilson, became a mother for the first time in October 2018 when she gave birth to their son Finn after IVF treatment.
She stepped out of the political frontline to go on maternity leave, with her deputy Jackson Carlaw standing in as interim leader.
She made her comeback speech to the Scottish Conservative conference in Aberdeen in May this year.
Her leadership has transformed the fortunes of the Conservatives north of the border after she took on the job in November 2011 - just six months after she became an MSP.
Under her, the Scottish Conservatives won a record 31 seats at Holyrood in the 2016 election, with the Tories ousting Labour from second place.
She cemented this result with a strong performance in the 2017 general election, when the party returned 13 MPs from north of the border - a result that helped keep Mrs May in Downing Street.
After Mr Johnson took over as PM, Ms Davidson lobbied to keep David Mundell - who she had previously described as her "work husband" - in post as Scottish Secretary, only for him to be sacked from the job.
Scottish Labour leader Richard Leonard said the loss of Ms Davidson would be a "real blow to her party".
The Labour MSP added: "This shows that even within his own ranks, Boris Johnson is already losing support and credibility."
Ruth Davidson's resignation letter to Scottish Tory chiefs in full
It has been the privilege of my life to serve as the leader of the Scottish Conservative and Unionist party.
The almost eight years I've spent at the helm have coincided with one of the most remarkable and important periods of recent Scottish political history.
I am proud of the teams we have built in Holyrood, Westminster and in council chambers across the country and proud of our electoral successes in recent years.
All of that pales in significance compared to vital role our party undertook in the Scottish independence referendum of 2014.
I will always consider that the most important contribution of my working life and my commitment to keeping the United Kingdom together remains undimmed.
None of the achievements mentioned above would have been possible without your support, guidance and friendship - along with the hard work and professionalism of the Scottish Conservative team at central office.
For all of this, thank you.
Inevitably, much has changed over the years of my leadership — both personally and in the wider political context.
While I have not hidden the conflict I have felt over Brexit, I have attempted to chart a course for our party which recognises and respects the referendum result, while seeking to maximise opportunities and mitigate risks for key Scottish businesses and sectors.
I hope and believe that industries as diverse as our fishing fleets and whisky producers have felt well represented by the Scottish Conservatives during this time.
The biggest change, of course, has been starting a family.
I cannot thank you, Jackson Carlaw and the wider party enough for the generosity and support you have all shown to Jen and me following the birth of baby Finn.
It made my return to work in April as smooth as I could have hoped and I believe the flexibility shown by colleagues has allowed me these last months to continue operating successfully in my role as leader.
However, as I look to the future, I see the Scottish Election due in 2021 and a credible threat from our opponents to force a general election before then.
Having led our party through seven national elections and two referenda, I know the efforts, hours and travel required to fight such campaigns successfully.
I have to be honest that where the idea of getting on the road to fight two elections in 20 months would once have fired me up, the threat of spending hundreds of hours away from my home and family now fills me with dread. That is no way to lead.
Additionally, 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.
While I offer you my resignation as party leader, I intend to continue in my role as the MSP for Edinburgh Central until 2021.
I will always be thankful for the opportunity to serve and to the amazing teams I have worked alongside. Be assured I will continue to support the party, the Prime Minister and Scotland's place in the United Kingdom from the backbenches and beyond.
Yours sincerely,
RUTH DAVIDSON MSP
