The Prime Minister has told STV News he hopes to retain all his party's seats in Scotland and win more if there's a snap general election.

Boris Johnson refused to say how many of the current 13 Scottish Tory MPs he thinks he will keep but praised the "large amount of talent" on his Scottish benches.

He told STV's Westminster correspondent Kathryn Samson he wants to do a new Brexit deal with Brussels "if we possibly can" and defended his use of language.

Speaking on the first day of Conservative conference in Manchester, the PM also said he was "sad" Ruth Davidson quit as Scottish Tory leader last month.

It comes as interim Scottish Conservative leader Jackson Carlaw told the conference on Sunday the Scottish Tories would back a no-deal Brexit on October 31 if a deal cannot be reached with the EU.

Reversing Davidson's position opposed to a no-deal outcome, Carlaw told party colleagues across the UK that the "endless drift" of further delaying Brexit would be "far more damaging" than leaving without a deal.

Speaking to STV, the Prime Minister said: "I want to do a deal if we possibly can... and then come out regardless on October 31."

Quizzed on if his rhetoric was softening - after previously saying he would rather be "dead in a ditch" than postpone Brexit - Johnson answered: "No, let's be clear.

"I don't intend literally to be dead in a ditch, nobody's literally going to die, these are metaphors."

On the prospects for Conservative MPs north of the border in the next election, the PM said: "I'm not going to put a figure on it.

"I hope we win all the seats we've got and more."

Johnson also defended his sacking in July of former Scottish secretary David Mundell, who he replaced with Dumfries and Galloway MP Alister Jack, against the wishes of Ruth Davidson.

"I am a great fan of David Mundell and of all our Scottish MPs," he said.

"(I sacked him) because I wanted to make a change and because there is a large amount of talent on the Scottish benches."

His decision to remove Mundell against the advice of then-Scottish Tory leader Davidson drove an early wedge in the pair's relationship.

On Davidson, the Prime Minister said: "I think it was sad that Ruth went. I think she's a massive talent in our party...

"She's got a young child and she felt she should devote some time to that."