Lord Mandelson would have been subject to a "thorough" and "intimate" vetting process before he was appointed UK ambassador to the US, a former head of MI6 has said.

Sir Richard Moore, who left his post last September, told Sky News' lead world news presenter Yalda Hakim he had not been part of the process, amid more revelations about the ex-Labour peer's relationship with paedophile Jeffrey Epstein.

Sir Keir Starmer last week apologised to the public and to Epstein's victims for believing what he called "Mandelson's lies".

The prime minister insisted he was misled over the extent of Lord Mandelson and Epstein's links, saying he had "no reason" to believe the peer was allegedly lying when he said he barely knew Epstein before being made ambassador.

Sir Keir criticised the vetting process that Lord Mandelson went through. The Epstein files appear to show regular contact between the former Labour grandee and Epstein after the US financier's sex offence conviction in 2008.

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Speaking about background checks more broadly, former spy chief Sir Richard said: "Undoubtedly there would have been some background checks and then there's an interview process, where you rely to a degree.

"You've got the background checks, of course, to set it against, but you rely on people in those interview processes being very honest."

He added: "I've been through that many, many times. They can sometimes be uncomfortable conversations because you're being asked about very private elements of your lifestyle or about your financial situation, and you are required to answer those questions truthfully.

"And the system depends on the balance between truthful answers in the interview process and the checks on whether what's been said is truthful."

Read more: What do the Epstein files say about Mandelson?

Sir Richard said he was not aware of any intelligence relating to the peer's appointment as US ambassador, but even if he was, he would not be able to share it.

He added: "I'll say to you, I'm not aware of anything, but I repeat what I said, you have to understand the sensitivities of this, this stuff does not get circulated around the building. So the answer is, I have no idea."

He also called out what he described as the "rancid misogyny and appalling systematic abuse of women and girls" exposed in the Epstein files.

Lord Mandelson was appointed ambassador in December 2024 and was sacked by Sir Keir in September 2025 over the peer's ties to Epstein.

It comes as government figures prepare to hand over huge amounts of material to Parliament's security watchdog after they came under pressure to reveal what was known about the peer's friendship with Epstein when he was picked for the Washington job.

Meanwhile, the Metropolitan Police has launched an investigation following accusations that Lord Mandelson passed market-sensitive information to Epstein in 2009.

(c) Sky News 2026: Mandelson would have had 'thorough' vetting process before US ambassador role, says ex-MI6 boss