More than 1,000 pages of documents relating to Lord Peter Mandelson’s controversial appointment as the United Kingdom’s ambassador to the United States have been released, offering an unprecedented look into private government discussions, internal disagreements and security concerns surrounding the former Labour heavyweight.
Among the most notable disclosures is a handwritten note sent by Mandelson to then-Foreign Secretary David Lammy in November 2024, in which he pledged that the government would “never regret” appointing him to the high-profile diplomatic role.
The newly released files also reveal that Mandelson declined a request from the Cabinet Office to hand over information stored on his personal mobile phone.
Government officials noted that they had no legal authority to compel him to provide access to the device.
The publication follows a parliamentary vote earlier this year ordering the release of documents connected to Mandelson’s appointment and subsequent dismissal.
The former ambassador was removed from the role in September 2025 after fresh details emerged about his relationship with convicted sex offender Jeffrey Epstein.
Private WhatsApp messages included in the release show Mandelson expressing concerns about Prime Minister Keir Starmer’s leadership.
In one exchange with Cabinet minister Pat McFadden following Labour’s poor local election results in 2025, Mandelson remarked that “Keir lacks verve,” adding that the Cabinet also lacked energy and effective execution.
The files further reveal that senior security officials believed Mandelson should undergo the highest level of government vetting before taking up the ambassadorial post.
Correspondence from the Foreign Office’s chief security officer showed both the Foreign Office and Cabinet Office agreed he should complete the standard Developed Vetting process, citing the sensitivity of his role in Washington.
Other messages show Mandelson offering political advice to ministers and discussing government policy.
In one exchange with then-Technology Secretary Peter Kyle, he suggested a speech on artificial intelligence should contain more positive messaging before focusing on security concerns.
Kyle later thanked him and said he would incorporate the advice.
The documents also contain discussions about a proposed diplomatic gift for US President Donald Trump, including plans for a specially commissioned British government-style red dispatch box bearing the title “President of the United States.”
Government officials described the publication as the largest response ever made to a parliamentary demand for official records.
The release spans more than 1,500 pages across three volumes and includes emails, official memoranda, briefing notes and private messages exchanged between ministers, advisers and Mandelson.
Some documents remain withheld due to ongoing police investigations and national security considerations.
Mandelson remains under criminal investigation over allegations of misconduct in public office, though he has repeatedly denied any wrongdoing and insists he has not acted for personal gain.
The latest disclosures are expected to fuel further debate over the circumstances surrounding Mandelson’s appointment, the vetting process that preceded it and the government’s handling of one of the most controversial political controversies of recent years.
