Former PM Chief of Staff Reflects on Mandelson Appointment
The Prime Minister's former chief of staff, Morgan McSweeney, has acknowledged making "a serious mistake" in recommending Lord Mandelson for the position of the United Kingdom's ambassador to the United States.
McSweeney, who resigned in February following the controversy, initially believed that Lord Mandelson's background as an EU trade envoy would be advantageous in securing a trade deal with the US.
However, during testimony before the Foreign Affairs Committee, McSweeney revealed that after new information surfaced regarding Lord Mandelson's association with the late convicted sex offender Jeffrey Epstein, it became clear that the peer had not been fully transparent about the nature of their relationship.
Concerns Over Vetting and Security Clearance
McSweeney admitted that there was a desire within No 10 to expedite Lord Mandelson's appointment but emphasized that officials were never instructed to bypass any procedural steps.
He also refuted claims that he had instructed the Foreign Office "explicitly or implicitly" to ensure security clearances were granted "at all costs."
Despite concerns raised by vetting officials, the Foreign Office granted Lord Mandelson security clearance for the ambassadorial role. The Prime Minister has stated that neither he nor McSweeney, nor anyone else in Downing Street, were aware that the Foreign Office had overridden the vetting recommendations until recently.
Lord Mandelson was dismissed from his ambassadorial post in September 2025 after further revelations emerged about the extent of his relationship with Epstein. This included photographs of the two together and emails from Mandelson supporting Epstein during his 2008 sex offence charges.
McSweeney's Reaction to Revelations
McSweeney described his response to the disclosures as deeply distressing.
"When I saw the revelations it was like a knife through my soul," he said.
"The nature of the relationship that I understood he had with Epstein was not a close friendship," McSweeney added.
"How I understood it at the time was a passing acquaintance that he regretted having and that he apologised for.
What has emerged since then was way, way, way worse than I had expected at the time [of the appointment]."
Due Diligence and Follow-Up Questions
Prior to Lord Mandelson's appointment, a due diligence check—distinct from security vetting—was conducted by a Cabinet Office team and submitted to the Prime Minister. This report highlighted Lord Mandelson's ongoing relationship with Epstein after his conviction as a potential "reputational risk."
Following this, the Prime Minister requested McSweeney to send three follow-up questions to Lord Mandelson concerning his association with Epstein.
At the time, McSweeney believed the responses were truthful but later acknowledged that Lord Mandelson had not provided the "full truth." The subsequent revelations from the Epstein files led McSweeney to conclude that Lord Mandelson was "unfit" for the ambassadorial role.
When questioned about the appropriateness of McSweeney, a friend of Lord Mandelson, handling these follow-up inquiries, he conceded that, in hindsight, it would have been "much better" for the Cabinet Office's propriety and ethics team to manage them.
Nevertheless, McSweeney expressed uncertainty that the Cabinet Office "would have got better answers."
Foreign Office Officials' Testimonies
Sir Philip Barton, the senior civil servant at the Foreign Office during the period, testified that Downing Street had shown little interest in the vetting process, focusing instead on ensuring Lord Mandelson's appointment was finalized before Donald Trump's inauguration.
This corroborated the account of his successor, Sir Olly Robbins, who described "pressure" from Downing Street to expedite vetting and characterized No 10's attitude as "dismissive" of the process.
However, Sir Philip denied that this pressure influenced the substantive content of the vetting decision.
McSweeney on Vetting Process and Allegations
Responding to these claims, McSweeney acknowledged that the Prime Minister's private office did seek updates from the Foreign Office regarding Lord Mandelson's vetting status.
He reiterated that Downing Street wanted the process completed "quickly" to ensure Lord Mandelson was in place by Trump's inauguration but insisted that no steps were skipped.
"Yes we wanted it done quickly but at no point did I witness anyone being dismissive about DV [developed vetting] or national security," he stated.
McSweeney also denied reports that he had sworn at the top Foreign Office civil servant while requesting approval for the appointment.
Sir Philip Barton confirmed he had no recollection of being sworn at by McSweeney.
for our Politics Essential newsletter to keep up with the inner workings of Westminster and beyond.
