Sir Keir Starmer has apologized to the victims of Jeffrey Epstein for believing Lord Mandelson's 'lies' and appointing him as the UK's ambassador to the US.

The prime minister began a planned speech on funding to improve local communities by addressing the growing anger over how he had dealt with the issue.

While he acknowledged it had been publicly known for some time that Lord Mandelson knew Epstein, he said: 'None of us knew the depths and the darkness of that relationship.'

However, Conservative leader Kemi Badenoch said the PM's position was 'untenable', while the Liberal Democrats called for a confidence vote to see if Labour MPs supported him.

The prime minister is facing calls from some of his own MPs to stand down.

Seeking to defuse the row in a speech earlier, Sir Keir said he regretted appointing Lord Mandelson and would not have done so if he had known what he knows now.

Directly addressing Epstein's victims, he said: 'I am sorry, sorry for what was done to you, sorry that so many people with power failed you. Sorry for having believed Mandelson's lies and appointed him and sorry that even now you're forced to watch this story unfold in public once again.'

Sir Keir has promised to release files, which he says will prove Lord Mandelson lied about the extent of his friendship with Epstein when he was being vetted for the US ambassador role.

[...additional details about the backlash and political implications...]