David Mundell sacked as Scottish Secretary by Boris Johnson

David Mundell has been sacked from his role as Scottish secretary by Boris Johnson.

The long-serving Tory MP said he was "disappointed'' to be leaving the Government after nine years at the Scotland Office, but was "not surprised'' by the new Prime Minister.

He had previously said he would find it "extremely difficult'' to serve under Mr Johnson, but sources close to the former Scottish secretary said he had been prepared to stay in the Cabinet, despite differences with the new PM.

Mr Mundell announced his departure from the the Government on Twitter, pledging he would "of course'' support Mr Johnson's administration.

But he also vowed he would "hold him to account on his commitments to the union''.

The former Scottish secretary is one of a number of high profile ministers who lost their job almost immediately after Mr Johnson formally took over from Theresa May as the UK's latest prime minister.

As the Brexiteer prepared to bring in his own Cabinet team, he axed Penny Mordaunt from the post of defence secretary, as well as sacking housing secretary James Brokenshire and international trade secretary Liam Fox.

Mr Mundell, who was Scotland Office minister in the Tory/Liberal Democrat coalition government before becoming Scottish secretary - tweeted: "Disappointed but not surprised to be leaving the Scotland Office after 9 years.

"Will, of course, support the new Government, but 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!''

His departure comes despite Scottish Conservative leader Ruth Davidson urging the new PM to keep Mr Mundell in his top team.

She said: "In David Mundell, two Prime Ministers have benefitted hugely from a having trusted advisor and committed unionist in the Scotland Office. He's often been a calming influence through the most turbulent times.''

Ms Davidson hailed Mr Mundell's record in the Scotland Office as exemplary'', saying he had "held his nerve'' during the Scottish independence referendum and had thenfaced down Nicola Sturgeon when she called for a re-run'' of that ballot.

The Scottish Tory leader added: "He is passionate about opening doors for Scottish businesses in Whitehall and using the might of the UK Government to promote them abroad, having led countless overseas trade delegations.''

After having campaigned for the UK to remain in the European Union in the 2016 referendum, Mr Mundell had gone on to voice concerns about the impact a no-deal Brexit could have on the UK.

A source close to the former Scottish secretary said: "He would have been prepared to make compromises and serve in a Boris cabinet on the basis that he feels Scotland is at a very critical moment, with the First Minister demanding an independence referendum next year, and on the basis that Boris says he wants to get a (Brexit) deal.''

While Mr Mundell would have remained in government, he is "not surprised'' to be leaving, with the source stressing he was "very proud'' of what he had achieved over the years, including the introduction of new powers for Holyrood in the 2016 Scotland Act.

He also became the first openly gay Conservative MP to hold a position in the UK cabinet after he came out in January 2016.