Morgan McSweeney, the prime minister’s former chief of staff, gave his first public appearance at a high-stakes hearing of the foreign affairs select committee to be grilled on the appointment – and vetting – of the disgraced US ambassador Peter Mandelson. He was preceded by the former Foreign Office chief Philip Barton, the man who oversaw the early formal process for Mandelson’s appointment. Here’s what we learned.
1. Barton felt pressure to get Mandelson appointed before Trump’s inauguration
Barton said that there was “absolutely” pressure on the Foreign, Commonwealth and Development Office (FCDO) to get Mandelson to Washington as quickly as possible, though he drew the same distinction as the prime minister that there was a difference between pressure to grant vetting and pressure to do the process quickly.
He said that Number 10 was “uninterested” in the vetting process, and the inquiries were about the pace at which he could arrive in Washington, ideally before the inauguration.
McSweeney said – in line with evidence given by Olly Robbins – that he never personally inquired about the progress of the vetting with the FCDO. “What I did not do was oversee national security vetting, ask officials to ignore procedures, request that steps should be skipped, or communicate, explicitly or implicitly, the checks should be cleared at all costs. I would never have considered that acceptable,” he told the committee.
But he did say that the public expected government decisions to be delivered quickly by civil servants. “There’s pressure in government every day, and most of that pressure comes from within,” he said. “No 10’s job in all of this is to make sure that the prime minister’s decisions are acted on quickly.”
2. McSweeney confirms he advised the prime minister to appoint Mandelson
Morgan McSweeney admits ‘serious error of judgment’ over Mandelson appointment – video The first person to propose Mandelson as ambassador was Mandelson himself, McSweeney claimed.
McSweeney said that appointing him “was a serious error of judgment … I advised the prime minister in support of that appointment and I was wrong to do so.”
He insisted his relationship with Mandelson had been deeply misrepresented – the two had barely met until 2017 and that Mandelson was uninterested in Labour Together, which was at that stage McSweeney’s project to persuade centrist MPs to stay in Labour and wait to retake the party from Jeremy Corbyn’s allies.
He said he saw him later as a “confidante” on matters of political strategy – but that he was not involved in candidate vetting or reshuffles, though he admitted Mandelson had offered advice on those.
But he said he believed that their priority at the time was to appoint someone who could secure a trade deal with the US – and that Mandelson’s trade experience made him the right candidate. “This was not some hero I was trying to get a job for,” he said.
Barton said there was no consultation of the Foreign Office. “I wasn’t involved, I wasn’t told a decision was coming,” Barton told the committee. He said the “die was cast” and that there was no possibility of advising against the appointment. “The normal order is vetting then announcement,” he said.
3. Both Barton and McSweeney had concerns about Mandelson’s Epstein connections
McSweeney said he had concerns about Mandelson’s friendship with Epstein, which he put in writing and received a reply.
That email is now being withheld by the Met police as part of their investigations. But he said he accepted Mandelson’s version of events that he and Epstein were not close friends.
“What is emerged since then was way, way, way worse than I had expected at the time. And it was when I saw the pictures, when I saw the [Bloomberg revelations] in September 2025, I have to say it was like a knife through my soul,” he said.
Barton said he was well aware of the “toxic” nature of the Epstein connection from his time in the US and his understanding of American politics. “I didn’t know anything that wasn’t in the public domain. Now we know a lot more about Mandelson’s links to Epstein.” He suggested the national security adviser, Jonathan Powell, also had concerns.
4. The ‘just fucking approve’ phone call is a myth
Both Barton and McSweeney have said it is untrue that McSweeney called Barton and told him “just fucking approve it” – a longstanding rumour, which most papers did not report as there was little evidence it occurred.
Barton said he had never spoken to McSweeney apart from in group meetings and that he had never sworn. McSweeney said the swearing rumour “is something that has caused me a great deal of stress for a number of months.
“I do not know why people do this in politics, put around untrue rumours. They phone lots of journalists. Those journalists then phone lots of politicians … It’s damaging for people’s reputations. And I think it’s unfair for staff who can’t speak for themselves.”
5. Neither knew Mandelson had failed the UK Security Vetting process
Barton swerved the question about whether it was the right choice to sack Robbins but admitted he had never before been involved in a process that had showed so many red flags.
McSweeney said that Number 10 “didn’t have a contingency plan [for Mandelson failing vetting] in place, but was always aware that somebody could fail security vetting, was always aware that that was a possibility for any appointment that we made”.
Asked if he thought Mandelson might fail vetting, McSweeney said: “No. And if it had happened, we’d have withdrawn the ambassadorship. It would have been a political embarrassment.”
6. There were few official records of conversations - and regrets over the process
Both Barton and McSweeney routinely failed to identify whether proper records were taken of conversations.
McSweeney admitted it had not been ideal for him and Labour’s communications chief, Matthew Doyle, to be the ones making inquiries to Mandelson about Epstein after the relationship was flagged in the initial due diligence. “When I look back on it, I certainly think it would have been much, much better if I’d asked PET [the Cabinet Office’s propriety and ethics team] to ask those follow-up questions,” he said.
“I guess my thinking at the time was if I put follow-up questions to him in writing, and that if a senior member of staff did that, that he would feel more obligated to give the truth and the full truth.” But he said it was “the prime minister’s decision” and that both had assumed the developed vetting process would delve deeper.
Barton swerved the question directly if due process was followed – especially as it was at the heart of the vote on referral to the privileges committee which was imminently under way in the Commons.
“The bit I was responsible for, up until I stepped down on Sunday 19 January, that was proper process, done at pace as we were asked … It was unusual for the announcement to be made before he vetted.”