Morgan McSweeney, Keir Starmer’s chief of staff, has quit his role as the prime minister’s closest aide amid anger over the appointment of Peter Mandelson as US ambassador.
The senior No 10 adviser’s position had grown increasingly untenable as pressure on the prime minister mounted over the scandal, which followed the release of emails underlining the extent of Mandelson’s ongoing relationship with the convicted child sex offender Jeffrey Epstein.
McSweeney resigned on Sunday, saying he took “full responsibility” for advising Starmer to appoint Mandelson, who had been a close ally and political mentor. He said the decision had undermined trust in Labour, the country and politics itself and it was the “honourable course” for him to go.
The departure of Labour’s most consequential political figure in recent years will come as a major blow to Starmer, who had come to rely on McSweeney’s political judgment, often over his own, even though No 10 came under fire regularly as a result.
In a statement released to the Guardian, McSweeney said: “After careful reflection, I have decided to resign from the government. The decision to appoint Peter Mandelson was wrong. He has damaged our party, our country and trust in politics itself.
“When asked, I advised the prime minister to make that appointment and I take full responsibility for that advice. In public life responsibility must be owned when it matters most, not just when it is most convenient. In the circumstances, the only honourable course is to step aside.”
Friends of McSweeney told the Guardian he planned to step away from politics for a time, even though his resignation from No 10 immediately prompted speculation he could return to his original role as electoral strategist at Labour’s headquarters.
But they suggested he was unlikely to stay on the sidelines for good, and could even return before the next general election. “Morgan has been doing this for 25 years, I’m sure he’ll get more involved again in future, but not right now,” one said.
Downing Street staff received an email on Sunday evening confirming that Starmer had asked Jill Cuthbertson and Vidhya Alakeson, McSweeney’s deputies, to take over as acting chiefs of staff, with immediate effect.
Labour MPs were divided in their response to McSweeney’s resignation. Some lamented his departure, highlighting his role in transforming the Labour party and winning an election landslide in 2024, and even suggesting their loyalty lay with him rather than Starmer. They suggested McSweeney had carried the can for Starmer over the decision to appoint Mandelson as ambassador to Washington. “Keir has just lost his firewall, on Mandelson and a whole load of other issues. Where does he think the anger gets directed next?” said one.
Allies of McSweeney said it was wrong to suggest he had pushed for Mandelson’s appointment. “He gave his advice, but that’s all it was. Keir made the decision.”
Since Labour took power, McSweeney had become a lightning rod for discontent among some backbenchers and grassroots members who were uncomfortable with the direction the party had taken on issues including immigration and welfare cuts.
They also criticised what they regarded as a “boys’ club” mentality and disdain for elected politicians. One suggested Starmer should have sacked his chief aide rather than giving him the opportunity to stand down first.
A senior MP said: “It’s about time. McSweeney was behind a string of terrible decisions because he cannot behave anything other than factionally. The wider lesson that has to be learned from this though is that we cannot operate a government where decisions are outsourced to a tiny faction of the party.”
In his statement, McSweeney said: “This has not been an easy decision. Much has been written and said about me over the years but my motivations have always been simple: I have worked every day to elect and support a government that puts the lives of ordinary people first and leads us to a better future for our great country.
“Only a Labour government will do that. I leave with pride in all we have achieved mixed with regret at the circumstances of my departure. But I have always believed there are moments when you must accept your responsibility and step aside for the bigger cause.”
He concluded: “As I leave I have two further reflections: firstly, and most importantly, we must remember the women and girls whose lives were ruined by Jeffrey Epstein and whose voices went unheard for far too long.
“Secondly, while I did not oversee the due diligence and vetting process, I believe that process must now be fundamentally overhauled. This cannot simply be a gesture but a safeguard for the future.
“I remain fully supportive of the prime minister. He is working every day to rebuild trust, restore standards and serve the country. I will continue to back that mission in whatever way I can. It has been the honour of my life to serve.”
The loss of McSweeney, who began his career trying to oust the hard left from Labour in Lambeth, south London, is particularly emblematic given his pivotal role in the Starmer project, tackling antisemitism in the party and securing a landslide election victory less than two years ago.
In a statement, Starmer said: “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. It is largely thanks to his dedication, loyalty and leadership that we won a landslide majority and have the chance to change the country.
“Having worked closely with Morgan in opposition and in government, I have seen every day his commitment to the Labour party and to our country. Our party and I owe him a debt of gratitude, and I thank him for his service.”
Despite McSweeney’s departure, pressure on Starmer over the scandal is likely to continue, with the release of hundreds of thousands of documents relating to Mandelson to the parliamentary intelligence and security committee. There is also an ongoing police investigation into alleged leaks of government information by Mandelson.
