British Prime Minister Keir Starmer’s chief of staff, Morgan McSweeney, resigned Sunday, accepting responsibility for advising the appointment of Peter Mandelson as U.S. ambassador despite his known links to Jeffrey Epstein. The departure of a key architect of Labour’s election victory plunges Starmer’s government into its most severe crisis just 18 months after taking power with a historic majority.
What Was the Direct Cause of the Resignation?
McSweeney’s resignation is a direct consequence of the ongoing scandal surrounding Lord Peter Mandelson, a senior Labour figure whose extensive communications with convicted sex offender Jeffrey Epstein were detailed in U.S. court documents released January 30. The files sparked a police investigation into whether Mandelson, as a minister during the 2009-10 financial crisis, leaked market-sensitive information to Epstein. McSweeney stated, “The decision to appoint Peter Mandelson was wrong,” adding, “When asked, I advised the Prime Minister to make that appointment and I take full responsibility for that advice.”
What Political Damage Does This Inflict on Starmer?
The crisis strikes at a moment of pronounced vulnerability for the Prime Minister. Despite Labour’s large parliamentary majority, Starmer faces low poll ratings after policy U-turns and now intense scrutiny of his judgment. The loss of McSweeney, a top strategist instrumental in Starmer’s rise, is a significant blow. Opposition leader Kemi Badenoch stated the resignation was overdue and that “Keir Starmer has to take responsibility for his own terrible decisions.” Within Starmer’s own party, one anonymous Labour lawmaker said, “It buys the PM time, but it’s still the end of days.”
What Are the Immediate Next Steps and Risks?
The government has agreed to release virtually all previously private communications among ministers regarding Mandelson’s 2024 appointment, with disclosure expected as early as this week. This creates a new imminent risk for Starmer, as the correspondence may reveal sensitive details about how his government planned to manage relations with U.S. President Donald Trump. Such disclosures could further damage Starmer’s standing and complicate diplomatic ties.
How Has the Mandelson Episode Unfolded?
Mandelson was appointed ambassador to Washington in 2024 but was sacked by Starmer in September 2025 after the extent of his Epstein links began emerging. Starmer spent the past week publicly defending McSweeney before his resignation, a strategy that opposition critics and some within Labour say raises further questions about the Prime Minister’s decision-making. In a statement Sunday, Starmer said it had been “an honour” working with McSweeney, who had served as chief of staff since October 2024.
FAQs: Key Questions Answered
Q: Who is Morgan McSweeney?
A: He was Prime Minister Keir Starmer’s chief of staff and a principal political strategist who played a key role in Labour’s 2024 general election victory.
Q: What is Peter Mandelson accused of?
A: U.S. court documents suggest he may have leaked market-sensitive government information to Jeffrey Epstein in 2009-10, prompting a UK police investigation for misconduct in public office.
Q: What did the Prime Minister say about the resignation?
A: Keir Starmer issued a brief statement calling it an “honour” to work with McSweeney but did not address the Mandelson scandal directly.
Q: What happens now?
A: The government is set to release internal communications about Mandelson’s appointment, potentially within days, which could trigger further political fallout.
Disclaimer: This information is based on inputs from news agency reports. TSG does not independently confirm the information provided by the relevant sources.
