Media playback is unsupported on your device Media caption Ruth Davidson speaks to Newsnight

The Scottish Conservative Party's leader says she is "not sure" Boris Johnson is "in a position to answer" questions about what would happen if the UK left the EU without a deal.

"In terms of the butterfly flapping its wings, and what are the consequences of that, I'm not sure I'm in a position to answer that and more importantly I'm not sure he {Mr Johnson] is," Ruth Davidson told Newsnight's Kirsty Wark.

She also said she does not think the 31 October deadline for Brexit "should be written in stone".

"There's nothing that's written in stone that says that if we're really close to a deal, at one minute past midnight on the 31, that actually we can't do that deal on the 1 [November]," she said.

This view is similar to that expressed by Jeremy Hunt, Mr Johnson's opponent in the Conservative leadership race, who has said he would consider a short delay to Brexit if a deal with the EU was close to completion. Ms Davidson has previously endorsed Mr Hunt.

Mr Johnson, on the other hand, has said he would ensure the UK left on 31st October "do or die".

'Not good for Scotland'

As part of a Newsnight Special being broadcast from Edinburgh to mark twenty years from the creation of the Scottish Parliament, Kirsty Wark also spoke to Nicola Sturgeon, Scotland's first minister. Asked whether she would prefer a Hunt or Johnson premiership, she replied: "With the greatest of respect that's asking me if I'd prefer to be run down by a lorry or a bus."

"I think both of them in different ways would not be good for Scotland. I don't think that any Tory prime minister who actually doesn't have a mandate from Scotland is a good thing for Scotland," she added.

While stressing that she was not endorsing Mr Hunt, Ms Sturgeon said: "I look at Boris Johnson right now, and I find it really difficult to get my head round how any rational person could seriously contemplate putting him into the highest political office."

The possibility Mr Johnson could win the leadership, she said, "gives you a sense of how out of kilter the whole UK political system has become and how out of touch the Tories are with mainstream opinion in Scotland."

Ms Davidson also criticised Mr Johnson's proposed tax plans, which would increase the threshold after which people pay a higher rate of income tax from £50,000 to £80,000.

She said "I don't think it's designed to help the Conservative Party, or indeed to help the country because I think that as a party we work best when we're making sure that we've got fair taxation aimed particularly at the lowest earners".

Long seen as being on the liberal side of her party, she said "I don't think that comes as a surprise to any of your viewers" that "I'm you know not from the same wing of the Conservative Party as Boris Johnson."

A spokesman for Mr Johnson said he held Ms Davidson "in the highest regard" and if elected Tory leader he "looks forward to working with her to secure a good Brexit deal which will strengthen our precious union".

Ms Davidson did disagree with Mr Hunt on abortion. She described his personal view that abortions should be limited to the first 12 weeks of pregnancy as a "terrible policy". Mr Hunt has said that he would not change the current 24 week limit if he became prime minister.

"It's also a devolved issue," Ms Davidson said, adding that none of the Scottish parties plan to change current abortion laws. She said she had not had a "fulsome" conversation on the subject with Mr Hunt and did not know the reasons behind his view.

Devolution

Ms Davidson said the Scottish parliament "has become the centre of Scottish civic and political life".

She remembered its founding during her time as a student, "hearing Concorde flying over my head while watching the pictures of Concorde flying over my head on the television.

"And I wasn't sure then what it would look like, what it would sound like, what it would mean. But it really has replaced Westminster as where the reporting comes from, where the policies come from. People think of this now as the place that runs Scotland."

Ms Sturgeon also gave her reflections on the anniversary. "I think the biggest general change has been the sense of self confidence that came to Scotland as a result of the parliament," she said.

"When you think about it 20 years in the grand sweep of history is the blink of an eye and yet this parliament in that time has become firmly established as the democratic heart of the country. I think Scotland as a country carries itself a bit more confidently as a result of the establishment of this place."