Keir Starmer’s former chief of staff Morgan McSweeney has denied telling officials that Peter Mandelson’s “checks should be cleared at all costs” and admitted he was “wrong” to advise the British prime minister to appoint the peer as ambassador to Washington.
In a statement before his testimony to the UK foreign affairs committee, which is holding an inquiry into Mandelson’s appointment, Cork-born McSweeney said: “The appointment of Mandelson as ambassador was a serious error of judgment. I advised the prime minister in support of that appointment, and I was wrong to do so.
Starmer is facing an onslaught of pressure in relation to the appointment of Mandelson to the influential position in late 2024, given his known ties to Jeffrey Epstein. Mandelson was fired in September 2025 after the extent of those connections became clear.
Speaking to the committee, McSweeney said: “I resigned because I believe responsibility should rest with those who make serious mistakes. Accountability in public life cannot apply only when it is convenient. The prime minister relied on my advice, and I got it wrong.
“It is also important, however, to distinguish between what I did do and what I did not do.
“What I did do was make a recommendation based on my judgment that Mandelson’s experience, relationships and political skills could serve the national interest in Washington at an important moment. That judgment was a mistake.
“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 that checks should be cleared at all costs. I would never have considered that acceptable.
“These processes are in place to protect our national security.”
McSweeney began his evidence to the committee of MPs by apologising to the victims of Epstein.
McSweeney told the committee: “First, I want to say something about the victims and survivors connected to Jeffrey Epstein.
“Too often discussions of public figures and appointments can lose sight of the human suffering at the centre of these matters. Women and girls were abused, exploited and scarred. They deserved protection then, and they deserve to be remembered now.
“I am sorry for any part this controversy has played in causing further hurt or distress.”
McSweeney later said he does not have “any recollection of” seeking official advice over whether Mandelson could serve as the UK’s ambassador to the US and as chancellor of Oxford University at the same time.
The former No 10 chief of staff said that the peer had told him he was interested in the Washington job and also going for the university position, and that “my view to him” was that “these are incompatible”.
Mandelson was “certainly lobbying” for the ambassadorship but appeared to be “hedging” because he did not know whether he was going to be appointed, McSweeney said.
The former adviser was asked about an Observer report citing sources saying he had sought official advice over whether Mandelson could do both jobs at once.
“I don’t think I would have, but I can’t say for certain,” he told the foreign affairs committee.
Pressed on why he would be unable to remember doing something like this, he said: “I can’t remember doing so. I think you’re right, I would have remembered – I’d remember it.”
Earlier, McSweeney denied that Mandelson was ever a “mentor” to him.
“He was a confidant for me. I didn’t regard him as my mentor,” he said.
“I first had a conversation with Peter Mandelson in 2017. I don’t think I really started to go to him for advice until about 2021, and I was 44 years of age then, so I didn’t regard him at all as a mentor.
“I got advice from him, and it was useful, but I also had other people around who were perhaps a bit more shy with the media, who I saw too for advice. I was working with… we brought in some extremely experienced people from the [Tony] Blair administration.
He later said: “This was not some hero I was trying to get a job for. I thought that his skills as EU commissioner would help us to get the trade deal that I think the country needed, because we were very, very exposed after Brexit and getting that trade deal right was very important.”
McSweeney denied that Mandelson helped to vet Labour candidates for the 2024 general election.
“Mandelson had nothing to do with the selection or the vetting of any of our parliamentary candidates,” McSweeney told the committee, after being asked by a story in The i Paper, which suggested the peer was.
The former No 10 chief of staff later said Mandelson was involved a Labour Party internal process “to determine the suitability of potential parliamentary candidates”, adding: “But Mandelson was not involved in the selection of our candidates.”
McSweeney also denied having met Mandelson while working as an intern for a Labour campaign database during the early Blair era, adding he reported to “much more junior people” while working at Excalibur in 2001.
He also denied that Mandelson was involved in the reshuffle triggered by the resignation of former deputy leader Angela Rayner in September last year.
Starmer faces the double threat of a standards investigation into his decision to appoint Mandelson as ambassador to the US.
Opposition politicians are trying to subject him to the privileges committee for an inquiry into whether he misled parliament over the appointment.
Allies including Richard Hermer, the attorney general, and Jenny Chapman, a UK foreign office minister, were among those who rang round Labour MPs before Tuesday’s Commons vote on whether to refer him to parliament’s privileges committee.
Senior Labour figures including Gordon Brown and former cabinet ministers Alan Johnson and David Blunkett called for restraint from backbenchers, dismissing the vote as a political stunt designed to destabilise the party before the May elections.
It is understood Labour MPs will be whipped to vote against a Conservative motion to refer Starmer to the committee. Any rebellion is likely to be limited because most appear to accept that, although there is anger towards the prime minister, they do not want to hand the opposition a win.
Starmer faced a second moment of jeopardy on Tuesday with McSweeney’s appearance in front of the foreign affairs committee (FAC) inquiry into Mandelson’s appointment.
Philip Barton, who ran the foreign office before Olly Robbins – the top official sacked by Starmer last week – also gave evidence to the foreign affairs committee on Tuesday. He said there was no substance to allegations that McSweeney had sworn at him while urging for the process of appointing Mandelson to move faster.
In a further development, a letter from Ian Collard – the director of security – to the committee on Mandelson’s vetting revealed on Monday night he had not seen the document that recommended security clearance was denied.
Instead, he received an oral briefing from officials who told him it was “overall … a borderline case” that could be handled through “robust risk management”. He admitted he felt under pressure to deliver a “rapid outcome” to the case, but that it did not have an impact on his final judgment.
In an attempt to bolster support among his own MPs, many of whom have been dismayed by the revelation that Mandelson was installed as ambassador despite failing security vetting, Starmer addressed the parliamentary party before the vote.
“I have responsibility for being totally transparent with you, with parliament and the British public,” he said. “I take that very seriously as well.
“But this is not about a lack of transparency. This is a political stunt by our opponents who want to bring us down, obscure our message, stop us getting on with our work. And the timing tells you everything, nine days before local elections … Tomorrow is pure politics and we need to stand together against it.”
Downing Street took the unusual step of releasing a letter from Chris Wormald, the former cabinet secretary, to Starmer last September in which he concluded that “appropriate processes were followed” during Mandelson’s appointment.
The Tories have also questioned the prime minister’s claim that there was “no pressure whatsoever” applied on the foreign office over the affair, when former official Olly Robbins had said there was.
No 10 has said Starmer’s comment referred specifically to the security vetting process rather than the broader appointment of Mandelson. Knowingly misleading parliament is considered a resigning offence for ministers.
Senior Labour figures accused the Conservatives of political point scoring and Downing Street said it was a “desperate political stunt” designed solely to inflict damage on the government before crucial elections next week.
Brown urged Labour MPs to “put the needs of the country first” at a time when there are “conflicts raging around the world” with serious consequences for the UK. He said Starmer deserved their support and dismissed the vote as a “parliamentary game”.
Johnson and Blunkett released a joint statement calling the Tory move a “nakedly political stunt with no substance”, dismissing comparisons with Boris Johnson’s referral to the privileges committee, which precipitated his departure as an MP, as “absurd”.
Emily Thornberry, the chair of the FAC, said she could not see the need for a second inquiry while the one she was leading was still taking place.
After the parliamentary Labour Party meeting, many MPs appeared convinced that with the crucial local and devolved elections approaching and the conflict in the Middle East, this was not the time to attempt to oust Starmer by initiating a standards inquiry.
One said: “I am firmly in the ‘stick with the PM’ camp. I can’t see how a new leader taking the reins just as the Iran inflation shock takes hold would be good for them, or the party.”
However, some Labour MPs believe Starmer should refer himself to the committee to avoid allegations of a cover-up, with one pointing out that former Conservative prime minister Boris Johnson did so to counter fury on the Tory backbenches, even though he ended up out of office. – Agencies