Britain's Deputy Prime Minister David Lammy signaled his support for Prime Minister Keir Starmer on Saturday over the ongoing row about the decision to appoint Peter Mandelson as ambassador to the United States.

Labor veteran Mandelson was appointed as ambassador by Starmer and subsequently sacked over his ties to the late sex offender Jeffrey Epstein, in a scandal that has brought the British leader's judgment into question.

Starmer on Friday faced renewed pressure to resign after the government said security vetting had recommended Mandelson not be appointed, but that Foreign Office officials had overruled that recommendation without the prime minister's knowledge.

Lammy, who was in charge of the Foreign Office at the time and is now deputy prime minister and justice secretary, told the Guardian newspaper it was inexplicable that Starmer had not been informed of the initial vetting recommendation.

British Foreign Secretary David Lammy walks along Downing Street on the day British Prime Minister Keir Starmer held an emergency meeting to discuss the Israel-Iran conflict, June 18, 2025.
British Foreign Secretary David Lammy walks along Downing Street on the day British Prime Minister Keir Starmer held an emergency meeting to discuss the Israel-Iran conflict, June 18, 2025. (credit: Chris J. Ratcliffe/Reuters)

"I have absolutely no doubt at all, knowing the PM as I do, that had he known that Peter Mandelson had not passed the vetting, he would never, ever have appointed him ambassador," Lammy told the newspaper.

Starmer has promised full disclosure 

The comments come ahead of a statement in parliament on Monday afternoon in which Starmer has promised to set out the full facts of what happened.

While political opponents have said his version of events is not credible and called for him to resign, senior members of his own Labor Party - including those seen as rivals for his position - have not publicly criticized him.

A lawyer for Mandelson did not comment on Thursday, when the Guardian newspaper first reported that he had failed part of the vetting process.