LONDON — Peter Mandelson assured the British government it would “never regret” appointing him as U.K. ambassador to the United States, according to documents released on Monday. His pledge was dramatically proved wrong within months.
More than 1,500 pages of files relating to the appointment of Mandelson, a friend of convicted sex offender Jeffrey Epstein, as envoy to Washington at the start of U.S. President Donald Trump’s second term were released by the government to comply with a demand by lawmakers.
They shed new light on the contentious decision and heap more embarrassment on beleaguered Prime Minister Keir Starmer.
Among the documents is a note from Mandelson to then-Foreign Secretary David Lammy in November 2024, before his appointment, pledging that the government would “never regret” giving him the post.
Starmer fired Mandelson after nine months when new details emerged about his friendship with Epstein, and fallout from the misjudged appointment has left the prime minister fighting for his job.
Alex Burghart, a lawmaker for the opposition Conservative Party, said that the decision to appoint Mandelson “is a failure that will define this prime minister’s premiership.”
“It is a failure that will be written as his political epitaph,” he said.
Mandelson’s security vetting process
A first trove of files published in March revealed ministers had been warned that Mandelson’s friendship with Epstein exposed the government to “reputational risk.”
It was later disclosed that Mandelson had been approved for the ambassador’s job despite failing security checks, a revelation that sparked bitter blame-trading between Starmer and senior civil servants.
The files released Monday show officials from multiple departments discussing Mandelson’s security vetting, a process that National Security Adviser Jonathan Powell described in previously released files as “weirdly rushed.”
One senior Foreign Office official said the primary issue was “trying to get 101 things done in a very short period of time.”
In one email, Mandelson asked vetting officials if he needed to tell them about “literally every foreign national I have ever met.” A Foreign Office official suggested he “send over the handful of names you mentioned. ... That will reassure the vetting team that you’ve been comprehensive, even if it’s all quite artificial.”
It remains unclear why Mandelson failed security checks. The summary of his vetting wasn’t among the documents released, as it’s part of a police investigation into Mandelson for alleged misconduct in public office.
Officials have said ties to Epstein are not the reason he failed the vetting. A background report drawn up by officials before Mandelson was appointed, released by the government in March, flagged business ties to Russia and China as a concern.
Also missing is any record of what measures, if any, were taken to mitigate the risk of giving Mandelson the job.
Mandelson refused to hand over information from his personal phone to officials, and the government “has no further recourse to search the personal devices of Peter Mandelson,” the documents say.
Mandelson, 72, was briefly arrested in February by detectives investigating allegations that he passed sensitive government information to Epstein when he was a Cabinet minister more than 15 years ago. He was released without bail conditions as the investigation continues.
Mandelson was seen as a Trump whisperer
Critics say Starmer’s decision to appoint Mandelson is evidence of bad judgment by a prime minister who has made repeated missteps since he led the center-left Labour Party to a landslide election victory in July 2024.
But at the time, many saw it as a savvy move to deal with an unpredictable president.
“I fear that navigating Britain’s interests through the Trump administration will require super-human skills and luck and a massive team effort,” Mandelson said in his November 2024 note to Lammy.
Mandelson’s expertise as a former European Union trade chief, charm and network of global contacts were considered assets in securing a trade deal with the Trump administration. It seemed to pay off, with a successful visit by Starmer to the White House in February 2025 followed by a U.K.-U.S. trade deal announced that May.
In a letter to Starmer before the trip, Mandelson said that “America first is the lodestar of his administration” and that the White House under Trump “will play the international system by a different set of rules.”
Mandelson noted in an email that the prime minister and president had developed a “strong personal bond.”
Starmer’s relationship with Trump later soured after the U.K. declined to join U.S.-Israeli strikes and other efforts in the Iran war. Some aspects of the trade deal remain incomplete.
Documents expose unflattering comments about Starmer
Details about Mandelson’s ties to Epstein, revealed in a huge trove of files published by the U.S. Justice Department in January, raised new questions about Starmer’s judgment, driving opponents and some Labour lawmakers to call for the prime minister’s resignation.
Those calls intensified after Labour suffered big losses in local elections in May. A senior Cabinet minister, Wes Streeting, resigned with the intention of challenging Starmer for the Labour leadership. Greater Manchester Mayor Andy Burnham is running for a seat in Parliament in a June 18 special election and is also expected to challenge Starmer if he wins.
The documents show that behind closed doors, Mandelson didn’t always give Starmer his full-throated support, and that government ministers also despaired at Starmer’s lack of leadership within months of him taking office.
“Keir is not leading from the front,” Cabinet minister Pat McFadden said in a May 2025 WhatsApp exchange with Mandelson.
Mandelson’s verdict was “Keir lacks verve.” He said that the government needed to act, “dare I say it ... in a more Trumpian risk taking and dare devil way.”
In July, he despaired that the government was “beleaguered and bereft,” and ministers don’t “really know what Keir thinks or wants.”
“In fact most of them don’t think Keir knows what he wants,” Mandelson said.
