Among the material released were exchanges involving Scottish Secretary Douglas Alexander.
Mr Alexander, like Mr McFadden, worked closely with Lord Mandelson during the Blair and Brown governments.
The files show him thanking the peer for support he gave in helping Mr Alexander secure reselection as a Labour candidate ahead of the 2024 general election.
Secretary of State for Scotland Douglas Alexander speaking during the Labour Party Conference at the ACC Liverpool. Picture date: Sunday September 28, 2025..
Lord Mandelson, a political appointment rather than a career diplomat, was sacked from his Washington role in September last year after more details of his relationship with Jeffrey Epstein emerged.
Sir Keir has been under fire over the decision to give Lord Mandelson the job despite it being known that his dealings with the billionaire paedophile continued after the financier’s conviction for child sex offences.
The documents were published following a humble address passed by Parliament demanding their release.
In WhatsApp exchanges with Mr McFadden in May 2025, following local election setbacks, Lord Mandelson wrote: “Keir lacks verve as does the Cabinet as a whole. People’s heads are broadly in the right place but you need more people who can execute.”
In further messages to Mr McFadden in July 2025, he described No 10 as “beleaguered and bereft” and said it required a “complete revamp and infusion of purpose and confidence”.
He also told Mr McFadden that Sir Keir was caught in a repeating cycle — “advance/buckle/advance/buckle” — citing retreats on immigration, welfare and Gaza.
Mr McFadden’s own messages showed him sharing frank views of his parliamentary colleagues. “Every meeting I have is ‘who can we tax in order to pay benefits to others’,” he wrote. “They’re asking the wrong questions.”
The files show that Mr Alexander messaged Lord Mandelson on the morning of the 2024 general election, describing the Tory campaign as “extraordinarily inept” and asking his view on the national result.
Lord Mandelson said he couldn’t tell, asking how Scotland was looking.
Mr Alexander told him there were around a dozen “hyper marginals” dependent on direct SNP-to-Labour transfers, with the SNP vote stabilised at around 30-33% — “much higher than the Tories in England”.
He said this put Labour in a range of 20-32 Scottish seats depending on field operations.
In the message, he admitted there was “v little enthusiasm for Labour but a quiet determination to secure change which is our greatest ally”.
Three days after the election, Mr Alexander sent Lord Mandelson a warm message of thanks.
Mr Alexander faced fierce local opposition to secure the party’s nomination for the seat , amid accusations that he was a carpet-bagger with no connection to the area.
Born in Glasgow, he was a Paisley MP for 18 years, until being unseated by 20-year-old Mhairi Black in the SNP tsunami of 2015.
The messages show he said the peer probably didn’t realise “quite how influential you’ve been in this whole improbable journey”.
He praised his encouragement two years earlier, including when the peer told Mr Alexander he was “going to have to become all Laboury again” and his “quiet and effective support when Gordon came out for [a third party, redacted] in the selection.”
Mr Alexander said he wouldn’t forget any of it, and added he would “value your counsel on Trade.” He signed off: “In gratitude and appreciation, Douglas.”
Lord Mandelson replied: “Any time.”
Exchange of messages between Alexander and Mandelson (Image: Gov.uk)
The files also included a handwritten letter from Lord Mandelson to then-foreign secretary David Lammy, written on House of Lords notepaper and dated November 18, 2024, in which the peer said the Government would “never regret” appointing him to the Washington role.
“I just wanted you to know that if you were minded to appoint me I would make sure you never regret it,” he wrote.
He added that navigating Britain’s interests through the Trump administration would “require super-human skills and luck and a massive team effort”.
Also revealed was Lord Mandelson’s assessment of a message from then-health secretary Wes Streeting urging the Government to recognise a Palestinian state.
He said Sir Keir needed to follow French President Emmanuel Macron and “up the ante” on Israel.
Mr Streeting said Israel is “committing war crimes before our eyes”.
In a WhatsApp exchange with Mr McFadden, Lord Mandelson described the missive as a “wild long hysterical message” that “reflects pretty badly on his maturity”.
Mr McFadden replied: “He is very active on the MPs WhatsApp groups on this subject.”
Before being appointed Ambassador, Lord Mandelson also used his position to lobby Labour ministers to support his bid to become Chancellor of Oxford University, sending unsolicited WhatsApp messages to Emma Reynolds, Ed Miliband, Shabana Mahmood and others urging them to register to vote.
He came fourth in the final five, with the role going to former Conservative leader Lord William Hague.
Pat McFadden sitting in front of a BBC Graphic of Lord Mandelson and Keir Starmer
The documents also showed Lord Mandelson apparently “declined to comply” with a request to hand over his personal phone and allow the Government to publish WhatsApp messages related to his appointment.
Chief Secretary to the Prime Minister Darren Jones told the Commons the Government had no powers to compel disclosure from Lord Mandelson as a third party, but said the Metropolitan Police’s criminal investigation could result in disclosure through the courts.
He also confirmed some messages “may not have been backed up” because of disappearing messages or changes in devices — including some of his own exchanges with the peer.
The SNP’s Westminster leader Dave Doogan said the appointment showed a “deep rot at the centre of the Labour government, from No 10 down”.
He added: “The Labour Party has serious questions to answer about why it gave Jeffrey Epstein’s friend such a powerful role in the UK Government, and allowed the scandal-plagued peer to wield such influence, despite it being a matter of public record that he maintained his close friendship with the convicted paedophile and had repeatedly been forced from office in the past.”
The Conservatives said the files represented a “failure that is visible from space”.
Shadow Cabinet Office minister Alex Burghart said: “It was the Prime Minister’s error. It was clear that due diligence was not followed. It is a failure that will define this Prime Minister’s premiership, it is a failure that will be written as his political epitaph.”
