SNP Westminster leader Ian Blackford has said he would "sound out" the possibility of a vote of no confidence in Boris Johnson if the Tory leadership front-runner became Prime Minister.
Mr Blackford said that Johnson's commitment to leaving the EU on October 31 with or without a Brexit deak was "prepared to follow a scorched earth policy" on Brexit which would have a "disastrous outcome" for Scotland and as a result "one of the options is to test the appetite for a motion of no confidence".
In the Sunday National Mr Blackford said: "Let's be clear, this man is prepared to follow a scorched earth policy where he is prepared to deliver a no deal when all the evidence points to the disastrous outcome for the economy of Scotland where we could lost up to 100,000 jobs."
He added the damage of Brexit to the Scottish economy could be "up to five times as damaging as the financial crisis. We are still paying the price for the austerity the Tories brought in, they are threatening the livelihoods of Scottish people again."
Mr Blackford also described a meeting he had with Theresa May and Boris Johnson, when he was Foreign Secretary, about a potential crackdown on Scottish Limited Partnerships and their use in money laundering, where the Tory leadership contender had no idea the issue was reserved and a direct responsibility of his department.
He added: "When I met Boris at number 10 his first comment was to ask why the Scottish Government wasn't legislating for this. I had to tell him we couldn't because it was a reserved matter. The bill we were seeking to attach to this was in his department. He was completely ignorant that he had responsibility for it."
Mr Johnson has refused to take part in tonight's Channel 4 Tory leadership hustings, although the five other contenders will all appear. The television channel has said it would "empty chair" the MP.
The second round of balloting of Conservative MPs will open tomorrow and Mr Johnson has agreed to appear in a BBC televised hustings on Tuesday night after the voting is over.