THERESA May’s Scottish parliamentary aide has warned Boris Johnson not to ignore Ruth Davidson for a second time.

The new Prime Minister ignored the Scottish Tory leader’s plea to keep David Mundell in the Scotland Office, instead sacking him and replacing him with Brexiteer Alister Jack.

In a sign of how fractured the party have become over the last week, West Aberdeenshire and Kincardine MP Andrew Bowie – who served as May’s private parliamentary secretary – told the BBC Johnson would be being “very reckless” and making a “grave mistake” if he ignored the party’s leader in Scotland again. Davidson, who had very publicly urged Johnston to back Mundell, was said to be furious at Downing Street’s decision.

In yet another blow to her authority, last night Johnson appointed an MP who represents an English constituency to be Jack’s junior minister.

Worcester MP Robin Walker was made parliamentary under-secretary at the Scotland Office, despite rumours it would go to one of the 11 other Scottish Tory MPs.

The National: Robin Walker has been appointed as Scottish Office parliamentary under-secretaryRobin Walker has been appointed as Scottish Office parliamentary under-secretary

Lord Ian Duncan, who had been junior minister, will leave the Scotland Office but keep his role at the Northern Ireland Office, and also take on a role at the Business Department.

Though well liked by his colleagues in Westminster, new Scottish Secretary Jack is not hugely popular with all of the party’s MSPs, who feel the multi-millionaire landowner with a penchant for shooting and hunting doesn’t reflect the image they want to portray in 21st century Scotland.

Yesterday, he was under fire after claiming the impact of a no-deal Brexit would be no more than “bumps along the way”. Responding to warning from Nicola Sturgeon and her Welsh counterpart Mark Drakeford about a “catastrophic” hard Brexit, Jack told the BBC: “Well, they’re both Remainers. They would say that.”

Last week, the Office of Budget Responsibility warned even the most “benign” no-deal Brexit would cause a recession, raise unemployment, cause house prices to tumble by 10% and increase UK debt with a £30billion black hole in public finances.

Asked if he believed his own government’s analysis, Jack said: “I don’t think no deal would be seriously damaging if we prepare for it properly.

“I do think there will be bumps along the way. I’m quite realistic about that. I think there are great opportunities for us as a nation on the other side of Brexit.

“I do think there may be some bumps if we end up with no-deal. It’s not my preferred option. But I do think, as the fifth strongest economy in the world, we can do great things.

“As I’ve always found in business, if you’ve got deadlines, and all the options are still on the table, you tend to get deals done if it’s in your interest. And it will be in their interest, with a £100bn trade surplus into the UK, as it will be in our interest to do a deal with them.”

The National: Mhairi Black MP

Mhairi Black condemned Jack’s remarks. “The Tory Scottish Secretary must apologise for these careless and revealing comments, which show he is completely detached from the reality of most people’s lives in Scotland,” the SNP MP said.

“As a multi-millionaire, landowning investor Alister Jack might be able to simply brush aside the catastrophic impact of no-deal Brexit – but the vast majority of people cannot afford a recession, or an outcome that threatens to destroy 100,000 Scottish jobs and cost every person in the country £2300 a year.

“It’s no wonder that support for independence is growing and the majority of people now want a fresh referendum.”