In September 2025, the British political landscape was shaken by revelations that would upend the career of Peter Mandelson, known in political circles as “Lord Mandelson,” and force Prime Minister Keir Starmer to act swiftly to preserve trust in the government and the diplomatic service.

Who is Peter Mandelson?

Peter Benjamin Mandelson, Baron Mandelson, has long been one of the most powerful figures in the Labour Party. A former Member of Parliament for Hartlepool, Mandelson’s résumé includes high-level Cabinet posts under Tony Blair and Gordon Brown: Secretary of State for Business, Innovation and Skills; President of the Board of Trade; European Commissioner for Trade, and other leadership roles.

In December 2024, newly elected Prime Minister Keir Starmer appointed Mandelson as the UK’s ambassador to the United States—a post usually reserved for seasoned career diplomats. Starmer said Mandelson would bring “unrivalled experience” in government and foreign affairs to strengthen the UK-US relationship.

What came to light

In early September 2025, files and emails from the estate of Jeffrey Epstein were made public, including a 2003 “birthday book” in which Mandelson described Epstein as “my best pal,” among other items.

Then, an email from 2008—after Epstein’s conviction—surfaced, in which Mandelson advised Epstein to “fight for early release” and expressed sympathy with him. These communications, critics say, paint a much deeper relationship than had been disclosed or understood when Mandelson was appointed ambassador.

Starmer’s Response and Fallout

Initially, when questions about Mandelson’s relationship with Epstein emerged, Prime Minister Starmer expressed confidence in Mandelson, while also stating that Epstein’s victims were “at the forefront of our minds.”

But as more evidence became publicly available—specifically the 2003 note and the 2008 email—Starmer was under growing pressure from opposition parties, media, and public opinion. Critics argued that Mandelson had not fully disclosed the nature or depth of his ties to Epstein.

On 11 September 2025, Starmer formally removed Peter Mandelson from the role of UK Ambassador to the US. Foreign Office minister Stephen Doughty told Parliament that the new correspondence revealed “the depth and extent” of Mandelson’s relationship with Epstein was materially different from what had been known at the time of his appointment.

James Roscoe is serving as interim ambassador in Washington.

Broader Implications

This episode raises several important questions for the UK government, Keir Starmer’s leadership, and the foreign service:

Vetting and transparency: How did these emails and ties slip through the vetting process before Mandelson’s appointment?

Political appointments vs. career diplomats: Mandelson’s designation as ambassador was unusual for someone with such a political past. Was this more risky than expected?

Trust and credibility: With international relations so fragile, especially with the US, what is the impact of such scandals on diplomatic credibility?

Starmer’s leadership tested: While Starmer moved decisively once evidence mounted, initial hesitation to act risked perceptions of tolerance for misjudgments in his inner circle.

What’s Next?

The government will need to select a new ambassador who is equally qualified but whose background is beyond reproach.

Calls for reform of the vetting process are likely, possibly even legal or procedural reviews to prevent similar oversight.

Political opponents and media are likely to continue probing any remaining undisclosed communications.

For Starmer, this is both a challenge and an opportunity: handling this transparently could help strengthen public trust; mishandling could harm his administration’s reputation on ethics and foreign affairs.

Conclusion

The Mandelson affair is a dramatic reminder that in high office, past associations—even if long dormant—can rapidly become central. It also shows that leadership demands not just capability, but integrity, transparency, and the ability to navigate crises. Keir Starmer’s choice to remove Lord Mandelson marks a critical moment in his premiership—a test of how the new government upholds its values while facing murky shadows from the past.