Ruth Davidson will call on her party colleagues to get back to Conservative principles and agree a Brexit deal or risk "handing the keys of Downing Street" to Jeremy Corbyn.
The Scottish Tory leader is due to address the party’s autumn conference in Birmingham later on Monday. In her speech Ms Davidson will say: “As we approach these crucial few weeks and months, we need to go back to our Conservative principles. The principles of country, of duty, of practicality and of delivery.
“The belief that every prudent act is based on accommodation and accord... The attitude that listens, eyebrows raised, to ivory-towered schemes of the ideological puritan and replies, aye, right.
“It’s this practical, pragmatic and utterly Conservative approach that will get us through. Because when the future of our country is at stake it is essential.”
She will add: “Here’s the truth: We can agree a Brexit deal under the Conservatives, or we can risk handing the keys of Downing Street to Jeremy Corbyn. I know which one I believe is in the national interest. I stand by the prime minister.”
‘Period of silence’
On Sunday, Ms Davidson called for a “period of silence” among her colleagues to allow the prime minister to get a Brexit deal “over the line”.
She said the two years following the EU referendum had given enough time for debate, and urged others to give their support to Theresa May.
Her comments follow Boris Johnson’s description of the Chequers proposals as “deranged and entirely preposterous”.
Speaking on the BBC's Sunday Politics Scotland, Ms Davidson said: "In terms of a period of silence, I would be very welcoming of one."
Ms Davidson, who is eight months pregnant, tweeted a video on Saturday of her receiving baby gifts from the prime minister as they met to discuss Brexit, the budget and the conference.