Boris Johnson has undertaken the bloodiest cull of a Cabinet in modern political history, as 17 senior ministers left government.

In a move that went even further than Harold Macmillan’s infamous “night of the long knives” in 1962, the new Prime Minister ruthlessly swept aside a raft of colleagues, including his leadership challenger Jeremy Hunt and Scottish Secretary David Mundell.

In their place, he promoted a raft of Brexiteers and allies.

At the end of a day of drama at Westminster when Mr Johnson took over the mantle of power from Theresa May, Nicola Sturgeon wrote to the new PM, calling on him to convene a meeting of the heads of government “as soon as possible”.

READ MORE: SNP say Ruth Davidson ‘humiliated’ after David Mundell sacked against her advice

The First Minister drew attention to work carried out by the Scottish Government which detailed the likely impact of a no-deal Brexit on Scotland, including the loss of 100,000 Scottish jobs.

“Given the gravity of the potential damage to jobs and livelihoods, this material should be at the top of your in-tray,” she declared.

Ms Sturgeon stressed that given Mr Johnson’s “do or die” vow on delivering Brexit by October 31, it was now essential Scotland had an alternative option and urged the new PM to respect the right of Scots to hold another independence referendum to determine their future.

In Mr Johnson’s brutal reshuffle Sajid Javid moved from the Home Office to be appointed Chancellor, the job he coveted, while Dominic Raab, the former Brexit Secretary, received the biggest promotion of all by not only becoming Foreign Secretary but also the First Secretary of State, making him Mr Johnson’s deputy. Priti Patel, another ardent Brexiteer, was made Home Secretary while leading Leaver Michael Gove was promoted to the role of Cabinet Office Minister.

Arch-Brexiter Jacob Rees-Mogg has been appointed leader of the House of Commons.

The Herald: Camley's cartoon: Mundell sacked in cabinet bloodbath.Camley's cartoon: Mundell sacked in cabinet bloodbath.

Alistair Jack, the MP for Dumfries and Gallery, replaces Mr Mundell at Dover House. As a whip the Scot has kept a low media profile but this will now change.

Mr Mundell has been a critic of Mr Johnson and would have found it difficult to sign up to the so-called “no-deal loyalty pledge,” which the PM had issued. But the Dumfriesshire MP had wanted to stay at Dover House, believing he was the best person to defend the Union at Westminster against the Nationalists.

He tweeted: “Disappointed but not surprised to be leaving the Scotland Office after nine 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."

Ruth Davidson, the Scottish Conservative leader, said her party owed her colleague a debt of gratitude. “In David Mundell, two Prime Ministers have benefited 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.”

ANALYSIS: A legacy torpedoed by Brexit

But the SNP, who had repeatedly called for Mr Mundell to be sacked, claimed his dismissal was a “humiliation” for Ms Davidson, whom it branded a “busted flush”.

Tommy Sheppard, the Nationalist backbencher, declared: “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.”

Earlier in his speech from the steps of Downing St, Mr Johnson insisted he would deliver Brexit by October 31 “no ifs or buts”.

He denounced the pessimists, who said Brexit could not be done, and declared: “I am standing before you today, to tell you the British people, that those critics are wrong; the doubters, the doomsters, the gloomsters are going to get it wrong again."

Tom Watson, Labour’s deputy leader, tweeted: "This huge cull will lead to early collapse of Johnson's govt bringing GE that much closer."

The SNP’s Pete Wishart said the appointment of “rabid right-wingers and extreme Brexiteers” had created a "Cabinet from hell," which Donald Trump would be proud of.