BORIS Johnson’s chief adviser Dominic Cummings has left his role after Downing Street became gripped by a bitter power struggle.

The BBC’s political editor Laura Kuenssberg announced the news on Twitter last night, saying Cummings and the Prime Minister had decided it was best for the aide to resign immediately rather than waiting until the end of the year as reported earlier in the day.

Tweeting the news of his departure, she added: “This was all a slow-burning fuse but exploded fast when it finally happened! End of a very torrid era.”

The controversial aide was later seen leaving Downing Street carrying a large box. His departure followed the resignation on Wednesday of senior Johnson aide and Cummings ally Lee Cain.

Johnson reportedly held a 45-minute meeting with the two men yesterday lunchtime about their "general behaviour".

The Prime Minister accused the Vote Leave veterans of briefing against him and his partner Carrier Symonds, and showed them text messages forward to Symonds to back up his claim.

He also accused them of destablising the Government during tense Brexit negotiations and told them to "get out and never return", according to the Financial Times. However, ITV political editor Robert Peston has said these detailed claims are untrue.

Cain and Cummings are both expected to continue working from home on certain key projects until mid-December.

Commenting last night, SNP Westminster Leader Ian Blackford MP said: “Boris Johnson’s most senior advisers are abandoning the Prime Minister like rats on a sinking ship – just as the UK faces a devastating extreme Brexit, a second wave of coronavirus, and a growing Tory unemployment crisis.

READ MORE: BBC's Laura Kuenssberg under fire for ‘false’ Scottish independence report

“It tells you everything you need to know about this arrogant, incompetent and self-serving Tory government that they are ditching their responsibilities – at the exact moment their reckless decisions are causing the maximum damage to people across the UK.

“If the Prime Minister had a shred of integrity he would pack his own bags and go with them. His tenure has been beset by abysmal failure, utter incompetence, and the alienation of Scotland and the other devolved nations.

“Scotland has been completely ignored by Westminster under Boris Johnson. We now face the prospect of an extreme Brexit, a Tory power grab, and the worst economic crisis in decades. It’s no wonder that the growing majority of people agree that the only way to protect Scotland’s interests is to become an independent country.”

Tory MPs hope Cummings’s departure will prompt a reset of a Conservative Government which is struggling to deal with the pandemic, Brexit and seek a positive relationship with US president-elect Joe Biden – a critic of Brexit and Johnson.

However, Professor Alex de Ruyter of Birmingham City University claimed the Prime Minister is at risk of being further weakened in the coming months.

“Cummings’s influence will live on – particularly through his close association with Michael Gove and others at the heart of government. This might not be the last we see or hear of him. It certainly won’t be the last we hear of the changes that he has helped precipitate,” he said.

“The pressures on Boris Johnson to go will only increase over the coming months.

“Given the Government’s inept handling of Covid-19, continued Brexit disruption as we approach exiting the single market and customs union, and a US president-elect who has made no secret of his disdain for Johnson and set a red line in upholding the Good Friday Agreement, the Prime Minister’s position is at risk of being further destabilised.”

The SNP has said Johnson’s appointment of Cummings as his chief aide “caused lasting harm to the UK and irreparable damage to the Tory government” .

Conservative MPs have urged Number 10 to use Cummings’s departure as an opportunity to restore the values of “respect, integrity and trust”.

READ MORE: 'Rats on a sinking ship': Ian Blackford calls for PM to quit alongside Cummings

Labour told the Government to focus on the coronavirus pandemic and not “self-indulgent spin doctors”.

Meanwhile, the Treasury has settled an employment tribunal claim with a former aide who was fired by Cummings, with the PA news agency reporting that the Government will be paying out a five-figure sum.

The settlement with Sonia Khan, who advised then-chancellor Sajid Javid until she was escorted out of Downing Street by police, means Cummings no longer faces the prospect of giving evidence in the case next month.

UK Transport Secretary Grant Shapps argued that Cummings, whose infamy was cemented by his trip to Durham during the first lockdown, is leaving because his big projects of coronavirus mass testing and Brexit being “on the near-term horizon now”.

“He will be missed but then again we’re moving into a different phase,” Shapps told Sky News, adding that “advisers do come and go”.

Johnson worked with Cummings on the 2016 Vote Leave campaign and hired Cummings to be his senior adviser, when he became Prime Minister. Six months later the pair’s “Get Brexit Done” campaign message helped Johnson win a large majority in the General Election picking up Labour votes in Brexit supporting areas in the north of England.