British Prime Minister Keir Starmer’s chief of staff Morgan McSweeney has quit, he said in a statement, as pressure intensifies on Mr Starmer over his decision to appoint Peter Mandelson as ambassador to the United States.
Mr Starmer is facing what is widely seen as the biggest crisis of his 18 months in power over his decision to send Mr Mandelson to Washington in 2024, after files showed the extent of Mr Mandelson’s relationship to the late sex offender Jeffrey Epstein.
Mr McSweeney, a 48-year-old man from Co Cork, was Mr Starmer’s closest adviser and widely seen as one of the architects of Mr Starmer’s success in Britain’s July 2024 election.
He said in a statement that he had been closely involved in the appointment of Mr Mandelson.
In his statement, Mr 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.
“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.”
Morgan McSweeney seen arriving at the Lord Mayor’s Banquet at the Guildhall in the City of London
“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,” added Mr McSweeney’s statement.
Born in Macroom in Co Cork in 1977, Mr McSweeney departed for London at the age of 17.
He joined the Labour Party, inspired by the Good Friday Agreement, and in 2001 began working as an intern at Labour HQ.
After rising through the ranks, he became director of the think tank Labour Together in 2017, a group whose key aim was to oppose Corbynism and find a way to move the party away from the so-called ‘hard left’.
Keir Starmer said it was an “honour” to work with Morgan McSweeney
Mr Starmer subsequently chose Mr McSweeney as his chief of staff after his election as Labour leader in 2020.
Mr McSweeney was appointed head of political strategy after Labour’s ascension to government in 2024, an election victory in which Mr McSweeney’s role was widely lauded.
In a statement, Mr Starmer said it was an “honour” to work with Mr McSweeney, saying the Cork man had “turned our party around after one of its worst ever defeats” and that he “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,” Mr Starmer added.
It’s about time.
But once 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. https://t.co/KvVIhUmK6v
— Kemi Badenoch (@KemiBadenoch) February 8, 2026
Tory leader Kemi Badenoch welcomed Mr McSweeney’s departure, but said the Prime Minister should “take responsibility” for his actions.
She said on X: “It’s about time.
“But once 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.”
As predicted McSweeney has gone.
Labour are just continuing the chaos we saw under the Tories.
My money says Starmer won’t be far behind after Labour’s disaster in the elections this coming May.
— Nigel Farage MP (@Nigel_Farage) February 8, 2026
Leader of Reform UK Nigel Farage meanwhile said Mr Starmer will be out of No 10 soon.
The Reform UK leader said on X: “As predicted McSweeney has gone. Labour are just continuing the chaos we saw under the Tories.
“My money says Starmer won’t be far behind after Labour’s disaster in the elections this coming May.”
Read more: Who is Starmer’s Irish adviser at centre of Mandelson scandal?