Starmer’s chief of staff Morgan McSweeney resigns over Mandelson appointment
The chief of staff to Prime Minister Sir Keir Starmer has resigned following mounting criticism over the appointment of Peter Mandelson to the US ambassadorship.
Morgan McSweeney – who succeeded Sue Gray to the post in October 2024 – said the decision to nominate Lord Mandelson as ambassador to the US was “wrong” and he took “full responsibility” for advising the Prime Minister on the move.
Mandelson was removed from the role in September 2025 after a major drop of new Epstein files from the US Department of Justice revealed closer ties between the peer and convicted sex offender. But new details of the pair’s relationship have emerged in the last month after another drop of files putting Starmer’s team under fresh scrutiny to how much they knew about Mandelson’s relationship with Epstein in the first place.
McSweeney said in his resignation statement that the due diligence and vetting process “must now be fundamentally overhauled” after stating it failed to disprove Mandelson’s claims that he barely knew Epstein.
Starmer had attempted to manage the release of files relating to Mandelson’s vetting process but faced a fierce rebellion from Labour backbenchers led by former deputy leader Angela Rayner. The backlash has triggered independent scrutiny of the vetting documents, something Starmer had wanted handled by the Cabinet Office.
Leader of the Conservative Party Kemi Badenoch had called for Labour backbenchers to prevent the Cabinet Office from looking over the contents of documents before publication, adding it equated to a “cover-up”.
Starmer had ‘full confidence’ in McSweeney on Wednesday
During Prime Minister’s Questions on Wednesday Badenoch asked Starmer directly if he had confidence in McSweeney, to which the Labour leader said “of course he did”.
Reacting to McSweeney’s departure on Sunday, Badenoch posted on X: “One again with this PM it’s somebody else’s fault: ‘Mandelson lied to me’ or ‘Morgan advised me’.
“Keir Starmer has to take responsibility for his own terrible decisions. But he never does.”
Meanwhile, Starmer hailed McSweeney’s “dedication, loyalty and leadership” for his party’s election win and expressed a “debt of gratitude” but did not mention Mandelson in the statement.
The loss of the Prime Minister’s closest aide – and right-hand man who oversaw Labour’s general election campaign – marks a major blow to Starmer in an already bruising week where reports are circling of leadership challenges.
Work and pensions secretary and close Starmer-ally Pat McFadden pushed back against calls for a no-confidence vote.
He told the BBC’s Sunday With Laura Kuenssberg programme: “Maybe one way we can be different is to not drop the pilot after 18 months and to stick with a leader and have consistency in leadership.”
McSweeney’s former deputies, Vidhya Alakeson and Jill Cuthbertson, are reported to have been appointed joint acting chiefs of staff.
IN FULL: Starmer’s chief of staff’s resignation statement:
“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.
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.
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.”