Another Takes the Fall as Mandelson Scandal Deepens Around Starmer

A recent departure intensified scrutiny of the Prime Minister's leadership, exposed growing unrest within Labour, and sharpened questions over how long Sir Keir can survive the most serious crisis of his premiership.

Sir Keir Starmer's authority was dealt another severe blow on Saturday as his chief of staff, Morgan McSweeney, resigned from Downing Street, becoming the latest casualty of the deepening Lord Peter Mandelson scandal that continues to engulf the Government.

Sir Keir Starmer addresses Chinese and UK business delegations at House of UK reception in Shanghai, China, on January 30, 2026. | Source: Getty Images

McSweeney, one of Sir Keir's closest aides for nearly six years, stepped aside after admitting he had pushed for the appointment of Lord Mandelson as Britain's ambassador to the United States — a decision he conceded was "wrong."

Downing Street Chief of Staff Morgan McSweeney arriving into Downing Street on October 6, 2025, in London, England. | Source: Getty Images

In a statement announcing his departure, McSweeney said he was taking "full responsibility" for advising the Prime Minister to elevate the disgraced peer to the key diplomatic post in Washington DC, adding that "in the circumstances, the only honourable course is to step aside."

Morgan McSweeney and Jonathan Powell at the annual Lady Mayor's Banquet on December 1, 2025, in London, England. | Source: Getty Images

The resignation comes as Sir Keir faces the gravest crisis of his 18-month premiership, following renewed scrutiny of Lord Mandelson's friendship with convicted sex offender Jeffrey Epstein.

The fallout has intensified pressure within Labour, with MPs openly questioning whether Sir Keir can remain in Downing Street as the scandal continues to widen.

Sir Keir Starmer speaking during a press statements event at the Prime Minister's Office on January 31, 2026, in Tokyo, Japan. | Source: Getty Images

Anger had been steadily building among backbenchers, many of whom had demanded McSweeney's removal in recent days.

The departing chief of staff was widely viewed as a mentee of Lord Mandelson, and frustration had been directed at No10 over the decision to appoint the former Cabinet minister as Britain's top diplomat in the US.

Lord Peter Mandelson being interviewed by the media near the Houses of Parliament in London, England, on June 24, 2016. | Source: Getty Images

McSweeney's exit marks the second time Sir Keir has lost a chief of staff, following the acrimonious departure of Sue Gray in October 2024. As the political crisis unfolded, public reaction on social media was swift and unforgiving, with calls for further resignations and demands for an election growing louder.

One person commented, "The first fall guy has fallen! Now who will he take with him? Hopefully the lot of them! We need a general election asap!" Another said, "This. Country. Has. Had. Enough. Just. Go."

Others focused directly on Sir Keir's future, with one netizen typing, "One down, one to go !" while another shared, "Starmer quitting next I hope."

Questions over how long the Prime Minister could survive were also raised, with one comment reading, "How much longer can Starmer hold on for?" and another adding, "Shouldn't the captain go down with the ship ?? Utter cowardice if he doesn't."

Sir Keir Starmer leaving 10 Downing Street in central London, England, on February 2, 2026. | Source: Getty Images

The loss of McSweeney, the architect of Sir Keir's general election victory, represents a further destabilising blow to the Prime Minister's increasingly fragile grip on power.

Sir Keir Starmer departing 10 Downing Street to attend the Prime Minister's Questions at the Houses of Parliament on February 4, 2026, in London, England. | Source: Getty Images

McSweeney played a central role in Labour's transformation from opposition to Government after Sir Keir replaced Jeremy Corbyn as leader in April 2020. Given the closeness of their relationship, it had long been speculated that McSweeney would only leave Downing Street if Sir Keir himself were also forced out.

Sir Keir Starmer adjusts his glasses as he waits to deliver his speech at Horntye Park Sports Complex on February 5, 2026, in England. | Source: Getty Images

Instead, the resignation is being interpreted by many within Westminster as a last-ditch effort by Sir Keir to preserve his own position. Senior figures are already being discussed as potential successors, with Angela Rayner said to be engaged in leadership "manoeuvres."

Health Secretary Wes Streeting, Energy Secretary Ed Miliband, Armed Forces minister Al Carns, and Labour deputy leader Lucy Powell are also viewed as possible replacements.

Sir Keir Starmer delivering a speech at Horntye Park Sports Complex on February 5, 2026, in England. | Source: Getty Images

Meanwhile, Greater Manchester mayor Andy Burnham's leadership ambitions appear to have been dealt a setback after Sir Keir's allies reportedly blocked him from standing in the Gorton and Denton by-election.

Activists attach themselves to each other in front of the gates of the Houses of Parliament with a lock on, inside a papier-mache head of Keir Starmer on February 6, 2026, in London, England. | Source: Getty Images

Meanwhile, Sir Keir sought to draw a line under the episode by paying tribute to his departing aide, praising McSweeney for having "turned our party around" and saying he owed him "a debt of gratitude." In a statement issued on Sunday, the Prime Minister added:

"It's been an honour working with Morgan McSweeney for many years. He turned our party around after one of its worst ever defeats and played a central role running our election campaign."

Morgan McSweeney and Jonathan Powell at the annual Lady Mayor's Banquet on December 1, 2025, in London, England. | Source: Getty Images

He credited him with playing "a central role running our election campaign" and said Labour's landslide victory was "largely thanks to his dedication, loyalty and leadership." Sir Keir added that he had witnessed McSweeney's commitment "every day" and thanked him for his service.

Elsewhere, opposition figures were less forgiving. Tory leader Kemi Badenoch accused Sir Keir of attempting to deflect responsibility for Lord Mandelson's appointment onto his former chief of staff.

Lord Peter Mandelson during Day 2 of the Labour Party conference on October 9, 2023, in Liverpool, England. | Source: Getty Images

"Once again with this PM it's somebody else's fault: 'Mandelson lied to me' or 'Morgan advised me,'" she said, adding that Sir Keir "has to take responsibility for his own terrible decisions. But he never does."

Reform UK leader Nigel Farage also weighed in, saying on X, "As predicted McSweeney has gone. Labour are just continuing the chaos we saw under the Tories." He added, "My money says Starmer won't be far behind after Labour's disaster in the elections this coming May."

Liberal Democrat deputy leader Daisy Cooper said changing advisers would not address the underlying issue, insisting, "The Prime Minister can change his advisers all he likes, but the buck stops with him."

She called for an end to what she described as a "political soap opera," urging answers for the public and "justice for the victims and survivors of Epstein and his network."

Jeffrey Epstein photographed in Massachusetts, United States, on September 7, 2004. | Source: Getty Images

Sir Keir selected Lord Mandelson to serve as Britain's envoy to Washington in February 2025, but the appointment unravelled months later, with the peer dismissed in September after renewed attention focused on his connections to Epstein.

Lord Peter Mandelson at a memorial service of Alistair Darling at Edinburgh's St Mary's Episcopal Cathedral on December 19, 2023. | Source: Getty Images

Newly released US documents — known as the "Epstein files" — have since provided further detail about Lord Mandelson's relationship with the late financier.

The Metropolitan Police has launched an investigation into allegations that Lord Mandelson sent market-sensitive information to Epstein while serving as business secretary during the financial crisis under Gordon Brown's government.

Scotland Yard has said the probe into alleged misconduct in public office would "take some time," after officers searched properties in London and Wiltshire.

Lord Mandelson has denied that the files show any wrongdoing or personal gain, and has repeatedly said he regrets his friendship with Epstein.

Lord Peter Mandelson at the BBC Broadcasting House in London, England, on June 23, 2024. | Source: Getty Images

Labour pressure group Mainstream, which is backed by Burnham, said those involved in appointing Lord Peter Mandelson as US ambassador must face consequences. In a statement, it added:

"We now need to tear out the regressive politics of elite privilege and toxic factionalism that enabled this scandal – and which will only produce more – root and branch."

Lord Peter Mandelson at the St Patrick's Day breakfast he hosted at the British Embassy in Washington DC, United States, on March 14, 2025. | Source: Getty Images

Sir Keir now faces the prospect of yet another reset of his Downing Street operation, following a series of previous rethinks during his year-and-a-half in No10 — with mounting doubts over whether any reset will be enough to stem the damage.