Former Hartlepool MP Lord Peter Mandelson said the Government would "never regret" appointing him Britain's ambassador to the US, newly released files revealed.

The second tranche of documents relating to Prime Minister Keir Starmer's decision to give the prestigious Washington job to Lord Mandelson were released by the Government on Monday.

Lord Mandelson also apparently “declined to comply” with a request to hand over his personal phone and allow the Government to publish WhatsApp messages and other information related to his appointment, the documents showed.

He was sacked by the Prime Minister last September after leaked emails showed the peer sent supportive messages even as financier Jeffrey Epstein faced jail for sex offences.

Former UK ambassador to the United States, Peter Mandelson, pictured in London in April (Picture: Henry Nicholls)

placeholder image — Former UK ambassador to the United States, Peter Mandelson, pictured in London in April (Picture: Henry Nicholls)

Lord Mandelson was arrested in February this year on suspicion of misconduct in public office.

One handwritten note from him to then-foreign secretary David Lammy in November 2024 read: “Thankfully, the media speculation has gone away and I hope this was not too irritating to you.

“I just wanted you to know that if you were minded to appoint me I would make sure you never regret it.”

Navigating Britain's interests “through the Trump administration will require super-human skills and luck and a massive team effort”, he said, adding: “For me it would be the last thing I do in public life and it would be a huge honour to serve you and the Government in this role.

“So if you are up for it, so am I.”

The more than 1,000 pages of newly released documents also included records of WhatsApp exchanges between Lord Mandelson and a series of government ministers.

Lord Mandelson was highly critical of Keir Starmer in messages, saying the Prime Minister “lacks verve”.

In a message to Pat McFadden, a senior minister in the Cabinet Office in July 2025, he described 10 Downing Street as “beleaguered and bereft” adding “It requires complete revamp and infusion of purpose and confidence to get anywhere.”

In the same month, he said the Government “doesn’t do policy, generally speaking, well enough”, in a message to pensions minister Torsten Bell.

Ahead of their publication, the Prime Minister's official spokesman described the release of the documents as an "unprecedented piece of Government transparency".