Morgan McSweeney, Sir Keir Starmer’s former chief of staff, told the Commons Foreign Affairs Committee on Tuesday that discovering the full extent of Lord Mandelson’s relationship with the convicted sex offender Jeffrey Epstein felt “like a knife through my soul”, as he accepted responsibility for backing Mandelson’s appointment as Britain’s ambassador to Washington.
McSweeney said he had made a “serious error of judgement” in supporting the appointment and told MPs: “I advised the Prime Minister in support of that appointment, and I was wrong to do so.”
Giving evidence in Parliament, McSweeney said that when he backed Mandelson in December 2024 he did not understand the former Labour cabinet minister’s association with Epstein to be a close friendship. He said he believed Mandelson had described it as a limited and regretted connection, rather than the far deeper relationship later revealed in reporting published in September 2025.
Referring to those disclosures, McSweeney said they showed something “way, way, way worse” than he had understood at the time. That, he said, was the moment it felt “like a knife through my soul”.
He also apologised directly to Epstein’s victims and survivors, telling the committee that women and girls had been abused and should not be forgotten amid the political fallout from the case.
McSweeney rejected suggestions that No 10 had improperly pressured officials to ignore security concerns or predetermine the result of Mandelson’s vetting. He drew a distinction between wanting the process completed quickly and seeking to rush it through recklessly, and said that, with hindsight, he should have asked the Cabinet Office’s Propriety and Ethics Team to pursue further written questions.
His evidence is among the most politically significant heard so far by the committee because McSweeney was at the centre of the original appointment decision. He resigned on 8 February this year, saying the choice to appoint Mandelson had been wrong and that he took full responsibility for advising Starmer to make it.
McSweeney also told MPs that Mandelson’s selection had been shaped by the political circumstances in Washington. He said Mandelson’s experience, including as a former EU trade commissioner, was seen as useful in dealing with a second Donald Trump administration, and suggested he probably would not have been chosen had Kamala Harris won the 2024 US presidential election.
The controversy over Mandelson’s appointment has turned on two linked questions: what Starmer and No 10 knew about Mandelson’s relationship with Epstein when he was chosen, and what happened after security vetting raised concerns.
Starmer has said he decided on 18 December 2024 to appoint Mandelson after No 10 staff had put due-diligence questions to him on 10 December and final advice had been received on 11 December. The government formally announced the appointment on 20 December 2024.
Security vetting began only afterwards, on 23 December. UK Security Vetting later recommended on 28 January 2025 that Mandelson should be denied Developed Vetting clearance, according to official documents and subsequent evidence to MPs. Foreign Office officials granted that clearance the next day, 29 January 2025, despite the recommendation.
In a Commons statement on 20 April, Starmer said that if he had known before Mandelson took up the post that UK Security Vetting had recommended denial, he would not have gone ahead with the appointment. “I should not have appointed Peter Mandelson,” the Prime Minister said, while again apologising to Epstein’s victims.
Ministers say the decisive new information emerged in September 2025, when Bloomberg published fresh details from Mandelson’s communications with Epstein. The Foreign, Commonwealth and Development Office withdrew Mandelson as ambassador with immediate effect on 11 September 2025, saying the emails showed that the “depth and extent” of the relationship was “materially different” from what had been known at the time of his appointment. The department said that included Mandelson suggesting Epstein’s first conviction had been wrongful and should be challenged.
The affair has since widened into a broader dispute over whether Whitehall’s due-diligence and vetting systems worked properly, and whether crucial information was escalated to ministers and senior officials. Cabinet Office permanent secretary Cat Little told the Foreign Affairs Committee last week that the Foreign Office, as the relevant department, retained discretion over whether to grant clearance even after receiving UK Security Vetting’s recommendation.
McSweeney’s appearance came as pressure continued to mount on Starmer over what he and his office knew at different stages of the process. MPs were due later on Tuesday to vote on whether to refer the Prime Minister to the Commons Privileges Committee over opposition claims that he misled Parliament when he said “due process” had been followed in Mandelson’s appointment.
The government has already announced changes in response to the scandal, including a review of the national security vetting system and a new rule that diplomatic appointments will no longer be announced before security vetting has been completed.
Tuesday’s committee hearing forms part of the Foreign Affairs Committee’s continuing inquiry into Mandelson’s appointment, clearance and dismissal, with further documents still expected to be published in the case.
Join the Discussion
Have something to say? Join the conversation!
Sign in to share your thoughts and engage with other readers.
Sign In Create AccountNo comments yet
Be the first to share your thoughts on this article!