You can't run a government on WhatsApp. Or, more accurately, you shouldn't try to hide your backstabbing on it when Parliament holds the ultimate receipts.
The massive drop of the Peter Mandelson files on June 1, 2026, isn't just another dry political leak. It is a three-volume, 1,000-page wrecking ball aimed straight at Keir Starmer's administration. While No. 10 tries to spin this as an "unprecedented piece of government transparency," nobody is buying that line. The government didn't want to release these papers. They were forced to by a Conservative-led Humble Address after Mandelson was sacked as the UK Ambassador to the United States last September.
If you thought the first batch of documents in March was bad, this second tranche is completely excruciating. It shows a toxic mix of terrible judgment, security shortcuts, and senior ministers trading insults about their own boss behind his back.
Here is what is actually inside the files, what they tell us about the collapse of trust in Whitehall, and why the fallout is far from over.
The Mirage of the Model Ambassador
When Mandelson was appointed to the Washington post in late 2024, the official line was that his unmatched political weight made him the perfect fit to navigate British interests abroad. He even wrote a handwritten note to David Lammy, using his House of Lords stationary, promising that the government would "never regret" giving him the job.
It took less than a year for that promise to fall apart.
The primary reason Parliament demanded these files was Mandelson's long-standing connection to Jeffrey Epstein. We already knew from disclosures by the US Department of Justice that Mandelson kept up his friendship with the financier long after Epstein’s 2008 conviction for child sex offenses. What these new files show is how little the Foreign Office actually cared about managing that risk.
There are no real records of the supposed "mitigations" that were meant to keep the government safe from reputational damage. Instead, the documents show Mandelson receiving highly sensitive, high-level briefings before he even cleared basic security vetting. He genuinely believed that his status as a Privy Counsellor meant he didn't need to go through the standard security checks that apply to everyone else. He was wrong.
Backstabbing in the Cabinet Backroom
The real political damage isn't just about security clearance. It's the sheer contempt that Mandelson and senior Labour figures showed for Keir Starmer's leadership while trying to run the country.
The WhatsApp exchanges between Mandelson and Pat McFadden, the Work and Pensions Secretary, read like an episode of a political satire, except it is entirely real. In May 2025, after a string of brutal local election defeats, Mandelson texted McFadden stating bluntly that "Keir lacks verve as does the Cabinet as a whole."
It gets worse. Mandelson openly described the No. 10 operation as "beleaguered and bereft" after visiting the premises. He didn't rate the administration's ability to handle policy at all, writing that the governing system was a case of "rubbish in, rubbish out." He even openly mocked Wes Streeting's successor, James Murray, and called the broader policy approach on key international issues "pathetic."
McFadden wasn't exactly defending the fort either. The files show him joking about his own backbenchers, grumbling that Labour MPs only ever care about "who can we tax in order to pay benefits to others." Unsurprisingly, political opponents like Kemi Badenoch have already seized on these lines to brand Labour as the party of high taxes and economic mismanagement.
The Missing Messages and the Police Track
If you think this dump represents total transparency, look closer at what isn't there.
Mandelson flatly declined to hand over his personal mobile phone when the Cabinet Office requested access via his solicitors in March 2026. Because it was a personal device, officials admitted they had no legal recourse to force a search. On top of that, countless messages between the former ambassador and senior ministers are missing entirely due to the use of disappearing message settings or frequent device upgrades. At one point, a No. 10 official explicitly instructed colleagues to "delete all traffic on this."
More importantly, a significant portion of the files, including the actual summary of Mandelson's security vetting, has been withheld completely. The reason? A live Metropolitan Police investigation into alleged misconduct in public office.
Mandelson was arrested back in February 2026 by detectives investigating whether he leaked sensitive state secrets to Epstein during his time as a minister under the Blair government. While he has been released without bail and denies all wrongdoing, the ongoing criminal probe means the full picture remains hidden under a legal blanket.
What Happens Now
The strategy from the Prime Minister’s allies is to move past the scandal by pretending the release proves their commitment to open government. That approach won't work. The Scottish Greens have already labeled the culture at the heart of government as "rotten," and the continuous drip-feed of disclosures is keeping the political bleeding alive.
If you want to track how this story develops over the coming weeks, look at these specific areas:
- Watch the parliamentary select committees: MPs from the Intelligence and Security Committee will be pushing to see the redacted text that Darren Jones claimed was blocked purely for national security reasons.
- Track the police updates: The political survival of several cabinet members hinges on whether the Metropolitan Police investigation into Mandelson’s past conduct leads to formal charges.
- Monitor the frontbench fallout: Look closely at how Starmer manages McFadden and other ministers caught talking down his leadership. The internal trust within the cabinet is effectively gone.
This story isn't going away. The public didn't just get a peek behind the curtain of British diplomacy; they got a clear look at a government that appears deeply insecure, distrustful of its own leadership, and desperate to keep its worst habits off the record.
