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.

LONDON— 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 challenged vetting demands to list foreign contacts

Mandelson pushed back against security officials vetting him for the Washington ambassadorship when they asked him to list his foreign contacts.

Emails from January 2025 show he queried the scope of the process, claiming he could not list “every foreign national I have ever met.”

In response, a junior member of UK Security Vetting  (UKSV) team told Mandelson he should focus on “current or recent” contacts and “personal friendships” or “personal business contacts.”

An unnamed Foreign Office official advised him to send over a list of names to “keep UKSV happy,” and to “reassure the vetting team that you’ve been comprehensive, even if it’s all quite artificial.”

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.

And at the the PM himself

In late July 2025, Mandelson told McFadden the mood in No. 10 was “beleagured and bereft” after a visit.

After McFadden singled out certain individuals as “the best we have,” Mandelson replied: I agree but they don’t work as a team, they are not led and none of them really know what Keir thinks or wants.”

“In fact most of them don’t think Keir knows what he wants,” Mandelson added. 

While some ministers confided their own doubts with Mandelson

McFadden — one of Starmer’s closest allies — regularly confided his concerns about decisions taken by key No. 10 officials and cabinet colleagues with Mandelson over WhatsApp.

Messages exchanged throughout 2025 show McFadden had doubts about the communications strategy and personnel choices being pursued by No. 10, particularly in the wake of a disastrous by-election defeat for Labour, and amid a mutiny of backbench Labour MPs over the government’s welfare reform plans.

At one point, Mandelson asked: “How is No. 10 now in your view?.” McFadden responded: “Not good.” 

McFadden also complained about his colleagues.

Referring to a Cabinet away day in July, McFadden said: “People want him to succeed. Angela notably silent.” An apparent reference to the then Deputy Prime Minister Angela Rayner. 

Another minister Torsten Bell also communicated doubts to Mandelson. In July 2025, the pensions minister told Mandelson that “the big picture” for the government “is… messy.” 

When Mandelson suggested to Bell he was not intensely involved in the trade deal being discussed with the U.S., Bell replied this was not “massively reassuring.”

DBT was cut out of trade talks by No. 10

No. 10 cut the Department for Business and Trade out of trade talks in the days leading up to last year’s U.K.-U.S. trade deal amid concerns about leaks to the media.

In a WhatsApp exchange with former No. 10 comms chief Stephanie Driver, Mandelson complained about what he claimed was an “unbelievably irresponsible” briefing by DBT to journalists.

“We are reaching a critical time on trade negotiation here and it would be helpful if DBT could stop guiding papers eg FT,” Mandelson wrote. “We want the deal when agreed to make its own impact not conditioned by pre briefing.”

Driver replied that she shared his frustrations and said both special advisers and officials had been warned about the “risks and sensitivities” involved.

Referring to a Guardian report published on May 7 last year about a visit by senior British trade negotiators to Washington, Driver agreed with Mandelson that the story had likely originated from DBT. “We cut DBT out of conversations today, the risk is too high,” she wrote.

Two months later in July, Mandelson complained to Driver about an article by POLITICO’s Graham Lanktree about a planned trip by the then Trade Secretary Jonathan Reynolds to press Trump further on tariffs. “Hi. Can you stop this stuff from DBT?” Mandelson wrote. “We are trying our best here but this is totally counterproductive designed purely for a domestic audience.”

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.

A separate document show Mandelson arranged meetings with two of Britain’s highest ranking spooks before he was granted developed vetting clearance.

The then-ambassador-designate sought meetings with “C” — the head of MI6 who was at the time Richard Moore, and “Q” — who was gadgets chief to Blaise Metreweli, who went on to succeed Moore, early in January last year.

A civil servant noted Mandelson was “yet to receive his DV clearance” — but that he was being given access to higher classification material on a case-by-case basis because of his status as a Privy Counsellor.

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

Before he became ambassador, Mandelson promoted his podcast to 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.

This developing story is being updated.