Mandelson files

What the latest Mandelson files reveal — so far

Withering verdicts on Starmer’s top team and the inner workings of the security vetting system are included in second batch of documents covering Peter Mandelson’s appointment as U.S. ambassador to Washington.

By Sam Blewett, Mason Boycott-Owen, Eleanor Myers, John Johnston and Matt Honeycombe-Foster

Keir Starmer’s embattled government on Monday published a fresh tranche of files relating to Peter Mandelson’s short-lived and controversial time as Britain’s envoy to Washington.

More than 1,000 pages of internal government documents and messages shed light on the Labour grandee’s security vetting for the diplomatic job, his interactions with — and withering verdicts on — Starmer’s top team, and the run-up to and aftermath of his dismissal from his post.

Mandelson was sacked as Britain’s ambassador to the U.S. in September last year following revelations about his association with the late financier and sex offender Jeffrey Epstein. A police investigation into his conduct was launched, which led to his arrest. He has not been charged, and his lawyers have said he is cooperating with the investigation and his overriding priority is to clear his name.

Starmer has repeatedly expressed regret for appointing Mandelson, saying the Labour veteran had created a “litany of deceit” around his ties to Epstein. But he has faced a huge number of questions about Mandelson’s influence on the government and whether enough was done to probe his past before he was appointed.

POLITICO’s team is poring over the files. Here’s what we’ve learned — so far.

Mandelson said there would be no regrets

Mandelson wrote to David Lammy promising he would “never regret” appointing him to the top diplomatic post of U.S. ambassador. 

“I just wanted you to know that if you were minded to appoint me, I would make sure you never regret it,” Mandelson said in a handwritten letter to the then U.K. foreign secretary.

“I fear that navigating Britain’s interests through the Trump administration will require super-human skills and luck and a massive team effort,” he modestly added.

He took direct shots at Keir Starmer’s Cabinet

Mandelson was deeply critical of key members of Keir Starmer’s top team — in texts to minister Pat McFadden, the files show.

The then-U.S. ambassador said energy secretary Ed Miliband “couldn’t resist yesterday. So personal and stupid. If he had played differently it would have had [a] fraction of attention.”

The texts appear to refer to a disagreement between Miliband and former Prime Minister Tony Blair over net zero policies in late April 2025. Blair had said that limiting fossil fuels was “doomed to fail.”

Miliband was by no means the only Cabinet member Mandelson critiqued. The former U.S. ambassador attacked the chancellor’s vision: “I felt when Rachel was here that she was on a growth mission but without an argument about where the growth will come from or how.”

According to the messages, Mandelson feared Reeves was considering “a huge bank levy” to pay for winter fuel payments and ending the two-child benefit cap. “It would be tantamount to abandoning long term growth for short term [parliamentary Labour party] management,” he warned.

Mandelson had an email exchange with nuclear defense officials

The latest tranche of files suggests that the former U.S. ambassador had an email conversation with the Ministry of Defence’s chief of nuclear defense.

The email, which is redacted in its entirety, was sent from Madelaine McTernan, who is responsible for Britain’s continuous at sea deterrent (CASD) fleet of nuclear submarines.

Mandelson’s access to top-level clearance has come under repeated scrutiny following his departure from the role, including whether he should have been granted Developed Vetting by security officials.

He railed against ‘Thick of It’ shenanigans

Mandelson complained to Starmer’s then-chief of staff Morgan McSweeney that the “saga” of approving a gift for Donald Trump had become “like something out of [sic] Thick of It” — a popular British comedy satirizing Westminster politics.

Olly Robbins, the then-head of the Foreign Office, relayed that a red box with “President of the United States” inscribed upon it would be one of the gifts that “would mean the most to the President.”

Mandelson described the email process of approving such a gift as like something out of the popular BBC political comedy, adding: “I have gone tonto on this.”

But shamelessly promoted his own podcast

Mandelson promoted his podcast with Labour ministers.

In October 2024, Mandelson sent Leader of the House of Lords Angela Smith a WhatsApp message with a link to his How to Win an Election Podcast, adding: “Enjoy.”

Exchanges that same year also show him texting multiple ministers to back his bid to be Chancellor of the University of Oxford.

He refused to hand over WhatsApp messages

Mandelson has always said that he will cooperate with any police investigation looking into his conduct. However, he’s been less compliant with the U.K. parliament.

The sacked ambassador declined to comply with a Cabinet Office request for any information held on his personal phone as they sought to fulfil a Commons request for details relating to his appointment.

“The Government has no further recourse to search the personal devices of Peter Mandelson,” the U.K. government states.