Revealed: Mandelson failed security vetting for US role

Foreign Office overruled decision to ensure ambassador post Opposition calls for Starmer to quit 'if he misled parliament', Opposition calls for Starmer to quit 'if he misled parliament'

- Paul Lewis Henry Dyer Pippa Crerar

Peter Mandelson failed his security vetting clearance but the decision was overruled by the Foreign Office to ensure he could take up his post as ambassador to the US, an investigation by the Guardian can reveal.

According to a number of sources, Mandelson was initially denied clearance in late January 2025 after a developed vetting process, a highly confidential background check by security officials.

Keir Starmer had by then announced he would be making Mandelson Britain's chief diplomat in Washington, posing a dilemma for officials at the Foreign Office, who decided to use a rarely used authority to override the recommendation from security officials.

Mandelson's failure to secure vetting approval has not previously been publicly revealed, despite intense scrutiny over his appointment and the release by the government of 147 pages of documents supposed to shed light on the case.

Downing Street released a statement late yesterday confirming the Guardian's story. It stressed the prime minister had no knowledge that security officials had advised that Mandelson should not be given clearance, and said responsibility lay with the Foreign, Commonwealth and Development Office (FCDO).

"The decision to grant developed vetting to Peter Mandelson against the recommendation of UK Security Vetting [UKSV] was taken by officials in the FCDO," a government spokesperson said. "Neither the prime minister, nor any government minister, was aware that Peter Mandelson was granted developed vetting against the advice of UK Security Vetting until this week.

"Once the prime minister was informed he immediately instructed officials to establish the facts about why the developed vetting was granted, in order to enact plans to update the House of Commons."

Downing Street insiders said he was "furious" about having been kept in the dark about the vetting decision.