U.K. Prime Minister Keir Starmer's former chief of staff said Tuesday that he made a "serious mistake" by recommending Peter Mandelson be made U.K. ambassador to the United States, but denied interfering with the appointment process.
Morgan McSweeney told lawmakers on the House of Commons Foreign Affairs Committee that it had been "a serious error of judgment" to back Mandelson. The committee is investigating how Mandelson, a scandal-tainted friend of Jeffrey Epstein, was given the key diplomatic job despite failing security checks.
McSweeney said that "the prime minister relied on my advice, and I got it wrong." He apologized to Epstein's victims, saying "I am sorry for any part this controversy has played in causing further hurt or distress."
McSweeney's testimony came as Starmer faced more heat Tuesday over the appointment, with lawmakers set to vote on whether the U.K. leader should be investigated by a parliamentary standards watchdog over the ill-fated decision.
The testimony came before the whole House of Commons debates a demand by the opposition Conservative Party for Parliament's Privileges Committee to investigate Starmer's explanations of how Mandelson came to be appointed.
Conservative leader Kemi Badenoch said that Starmer had "misled the House of Commons repeatedly" when he said that "full due process" was followed over Mandelson's appointment.
A finding by the committee that Starmer misled Parliament would likely be a resigning offense. Even if lawmakers don't back the call for an inquiry, it's a potentially dangerous day for Starmer, who has spent weeks fending off calls to resign over the Mandelson saga.
Starmer fired Mandelson in September after new details emerged about the ambassador's friendship with Epstein, a convicted sex offender who died in prison in 2019.
Police opened an investigation into Mandelson in February over allegations that he passed on sensitive government information to Epstein when he was a member of the U.K. government in 2009.
McSweeney resigned in February, saying he took responsibility for appointing Mandelson as ambassador.
He's certain to be asked about allegations by Olly Robbins, the former top civil servant at the Foreign Office, that Starmer's staff pressured officials to rush through the confirmation so that Mandelson could be in the post at the start of the second term of President Donald Trump in January 2025.
Robbins' predecessor, Philip Barton, told the committee on Tuesday that he was concerned that Mandelson's known links to "toxic, hot potato" Epstein "could become a problem" in the future.
But he said that he wasn't consulted on the "political decision" to appoint Mandelson. It's rare but not unknown for U.K. ambassadors to be political appointees rather than career diplomats.
"I was presented with a decision and told to get on with it," said Barton, who left his job for unrelated reasons in January 2025 before Mandelson's security clearance was approved.
"There was pressure to get everything done as quickly as possible," he said, but denied there was pressure for a specific outcome.
Ian Collard, the senior security official who briefed Robbins on the security checks, told the committee in a written statement that there was "pressure to deliver a rapid outcome," though he said that it didn't affect his judgment.
Starmer has denied that anyone in his office put pressure on the civil service.
The prime minister fired Robbins earlier this month after the revelation that Mandelson was approved for the job against the recommendation of the government's security vetting agency. Starmer has called it "staggering" that Foreign Office officials failed to tell him about the security concerns.
Robbins has said that the concerns didn't relate to Epstein, though he hasn't disclosed what they were about.
Critics say Starmer's decision to appoint Mandelson is evidence of bad judgment by a prime minister who has made repeated missteps since he led the center-left Labour Party to a landslide election victory in July 2024.
Starmer already defused one potential crisis in February, when some Labour lawmakers urged him to quit over the Mandelson appointment. He could face a new challenge if, as expected, Labour takes a hammering in May 7 local and regional elections, which give voters a chance to pass a midterm verdict on the government.
It would require a large number of Labour lawmakers to vote with the opposition on Tuesday for Starmer to be referred to the Privileges Committee, which has the power to suspend lawmakers, including the prime minister, from Parliament, for breaches of the rules.
Starmer urged Labour lawmakers to "stick together" and vote against the motion, calling it a "stunt" timed to damage the government before the May elections.
Censure by the committee exerts considerable moral pressure on politicians to resign. Its investigation into lockdown-breaking gatherings in government offices during the COVID-19 pandemic helped end the political career of former Prime Minister Boris Johnson.
Johnson quit as a lawmaker in 2023 after the committee found that he had repeatedly misled Parliament over the "Partygate" scandal.
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