Keir Starmer would have stopped Lord Mandelson becoming UK ambassador to the US if he had known about security concerns, deputy prime minister David Lammy has said, as the political fallout intensifies. Speaking to the Guardian, Lammy said the prime minister would “never, ever” have approved the appointment had he been aware Mandelson failed the vetting process, adding the situation was “inexplicable”. The row centres on claims that Mandelson was appointed despite being refused high-level security clearance, with Downing Street insisting the prime minister was only informed this week.

Starmer is expected to face questions in parliament, with opposition parties ramping up calls for his resignation and accusing him of misleading MPs over earlier assurances that proper procedures had been followed. Lammy, who was foreign secretary at the time, said neither he nor his team were told about the outcome of the vetting process. “I have never had any official talk to me about vetting,” he said, suggesting the issue was not escalated through normal channels.

He also pointed to pressure within government to fill the Washington post quickly following Donald Trump’s return to the White House, saying there was a push to have an ambassador in place. Pressure builds as questions mount on vetting process The controversy has already led to the departure of Sir Olly Robbins, the Foreign Office’s top civil servant, who left his role this week amid the escalating crisis. Lammy described Robbins as an “outstanding” official and said he was “surprised and shocked” by his exit, noting he had only been in post for a short period when the vetting report was completed.

Foreign secretary Yvette Cooper has ordered a review into what information was shared with ministers and MPs, saying she is “extremely concerned” that warnings were not passed on earlier. BBC News reported that the vetting assessment recommended against granting Mandelson access to sensitive material, raising further questions about how the appointment was approved. The Foreign Affairs Committee is now expected to examine the issue in detail, with Robbins set to face MPs in the coming days.

Senior figures across politics have criticised the government’s handling of the situation. Conservative leader Kemi Badenoch said the episode showed a failure of leadership, while Liberal Dem leader Ed Davey has called for a formal investigation into whether Parliament was misled. Mandelson took up the ambassador role in early 2025 but was later removed, and the renewed focus on his vetting has brought the appointment process back under intense scrutiny at a politically sensitive time for the government.