DAVID Mundell, one of Theresa May’s most loyal ministers, has been sacked by her successor despite his desperate efforts to cling on as Scottish Secretary.

Mr Mundell, whose nine years at the Scottish Office was the longest stint of any minister in the government, was a victim of Boris Johnson’s unprecedented Whitehall cull.

Mr Johnson’s move threatens to deepens his rift with Scottish Tory leader Ruth Davidson, who had made it abundantly clear that she wanted Mr Mundell, 57, to remain in post.

The SNP said Ms Davidson had been “utterly humiliated” by her close ally’s sacking.

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Mr Mundell, a former MSP and Dumfriesshire MP since 2005, was a junior Scottish minister from 2010 to 2015 during the LibDem-Tory coalition, then Scottish Secretary after that.

A frequent critic of Mr Johnson in the past, Mr Mundell revealed his sacking on Twitter just before 6pm, saying he was “disappointed but not surprised”.

He said: “As I said to PM this afternoon I will also hold him to account on his commitments to the Union. Hope there’s still room on the backbenches!”

Soon afterwards, he posted a picture of two bottles of beer, with the caption: “I hear there’s more time for this sort of thing on the backbenches.”

He is expected to be replaced by fellow Borders MP and whip Alister Jack.

Mr Mundell’s departure was in spite of him backtracking on previous threats to resign if Mr Johnson became Prime Minister, behaviour which saw him branded a “shameless parody of himself” and “spineless as a jellyfish” by the SNP.

Indeed, just hours before his dismissal, he had been pilloried at Scottish Questions in the Commons for appearing to suck up to Mr Johnson in what proved a vain attempt to stay in post.

Ms Davidson said on Tuesday that Mr Mundell’s experience would be “invaluable” to Mr Johnson.

“If the Prime Minister chose to keep on David Mundell I would be very happy with that,” she said.

After the sacking, she said Mr Mundell’s ministerial record had been “exemplary”, and credited his “strategic brain” for helping to revive Scottish Tory fortunes.

She said: “He has been a trusted advisor to two Prime Ministers, held his nerve during the independence referendum, and faced down Nicola Sturgeon when she called for a re-run in 2017.

“The part could not have enjoyed so many recent successes without his input, effort and ability to make Scotland’s case to his government colleagues.

“On a personal level, David handled his coming out as the Conservatives’ first openly gay cabinet minister with customary care and grace.

“David understands the power of the Scotland Office to promote the United Kingdom - and to defend Scotland’s place in it. We all owe him a debt of gratitude.”

SNP MP Tommy Sheppard said Mr Mundell had been sacked despite “pathetically” pledging support for Mr Johnson’s no-deal cabinet.

He said: “Ruth Davidson is a busted flush - Boris Johnson has humiliated her and left her authority non-existent following the sacking of David Mundell as Scottish Secretary. That was despite her bid to keep him in post, which was completely ignored by the new PM.

“This is a clear sign from Boris Johnson about how little he rates Ruth Davidson and the Scottish Tories. He is ignoring them just as much as he will ignore the rest of Scotland through the course of his premiership.”

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Labour MP Lesley Laird said: “David Mundell’s time in the Scotland Office will be remembered for his spineless failure to stand up for our country’s interests instead of his party’s. The only job he cared about saving was his own, and in the end he couldn’t even manage that.”

Edinburgh Labour MP Ian Murray added: “This confirms our worst fears that the new Prime Minister is building a hardline Brexiteer Cabinet and the Conservative and Unionist Party has given up on Unionism. We now have nationalist leaders in Downing Street and in Bute House at the very time we should be building bridges, not creating barriers.”