Lord Peter Mandelson told the Government it would "never regret" appointing him as Britain's ambassador to the US, according to a note published alongside thousands of documents about the posting.
The second tranche of documents relating to Sir Keir Starmer's decision to give the prestigious Washington job to Lord Mandelson rather than a career diplomat were released by the Government on Monday afternoon.
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.
Transparency Effort
Ahead of their publication, the Prime Minister's official spokesman described the sweeping whole of Government effort to publish the documents as an "unprecedented piece of Government transparency".
Ministers were braced for embarrassing revelations ahead of the publication of the files, which include thousands of previously private WhatsApp messages exchanged between figures at the top of Government.
The Note
The note, dated November 18 2024, appears to have been written as Lord Mandelson was awaiting the results of a vote for Oxford University's next chancellor, a job he was said to be among the frontrunners for at the time.
The letter, written in blue pen on notepaper headed with Lord Mandelson's name and a House of Lords seal, read: "Dear David, As today (and all week) is polling day in Oxford and I am returning to London, I wanted to drop you a line, personally, about Washington.
"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."
WhatsApp Exchanges
The release showed Lord Mandelson exchanged WhatsApp messages with a series of government ministers.
On July 20 2025 he told pensions minister Torsten Bell "the government doesn't do policy, generally speaking, well enough".
Mr Bell told him: "That is definitely true – everyone seems to think it's someone else's job to get the policy right… Which is very odd."
Lord Mandelson replied: "As the saying goes, rubbish in rubbish out…"
Elsewhere, he said former transport secretary Louise Haigh's exit from government was "harsh" after she quit over a fraud offence.
In a message to her on November 29 2024, he said: "Lou, I am very sorry about this. You have been brave and loyal in your decision but it seems harsh given you were appointed in full knowledge.
"But you have acted in a way that enables you to come back later and everything you say and do now should be done with that in mind. Strong and honourable."
