While Downing Street insisted Lord Mandelson had already issued comments defending himself, Labour MPs have now said he should be sacked.
One anonymously briefed The Telegraph: “Mandelson has to be responsible for the associations and friendships that he forms. We can make a judgement quite legitimately on relationships that he has made.
“It’s not good enough to say: ‘Whoops, I shouldn’t be associated with him now.’ You shouldn’t have been associated with him then.
“The easiest way round this for Mandelson is to step down. He should put the reputation of Britain abroad first.
“He should realise the damage done and step down. If he refuses to do that, then the Prime Minister should do the right thing and sack him.”
A second added: “He ought to resign. He knows how to stand down, after all. This would be the third time at least.”
They were joined by victims of the financier, including 41-year-old Sarah Ransome, who demanded: “Something is really, really wrong here. Peter Mandelson should not be ambassador. He needs to be fired. He is unsuitable to be ambassador.”
Spencer Kuvin, the attorney who represented nine victims, added: “By allowing someone with clear ties to one of the worst sex abusers of our time to be ambassador is an insult to the victims of Epstein.
“This man should be questioned by the FBI and the UK Government immediately to find out what he knows and whether he has visited any of Epstein’s homes in the past.”
An official spokesman for Lord Mandelson told the BBC: “Lord Mandelson has long been clear that he very much regrets ever having been introduced to Epstein.”
The spokesman also referred to previous comments Lord Mandelson made to the Financial Times, in which he said: “I regret ever meeting him or being introduced to him by his partner Ghislaine Maxwell.”
In 2023, a close ally of Lord Mandelson told the Financial Times it is “obvious” he had no involvement in Epstein’s sexual abuse of young girls, given the US ambassador is gay.