Senior figures in Sir Keir Starmer's government are preparing to hand over tranches of their electronic communications with Lord Mandelson ahead of the release of evidence about his appointment as US ambassador.
The deepening scandal prompted an apology on Wednesday from Sir Keir to the victims of Jeffrey Epstein for believing Lord Mandelson's "lies" and appointing him when the peer's friendship with the paedophile was already public knowledge.
Despite the prime minister's attempt to defuse the row, some of his own MPs are calling on him to stand down.
It comes as No 10's former communications director warned the disclosure of private messages could drag more public figures into the scandal.
"I don't think anyone can understate the gravity of the situation," James Lyons told BBC Newsnight.
