Sir Keir Starmer has insisted he has complied with requests to handover his WhatsApp messages relating to Lord Peter Mandelson, after it was revealed the Prime Minister uses disappearing messages on the communications app.The disappearing message feature on WhatsApp means conversations between the prime minister and Lord Peter Mandelson may have been deleted and lost.No 10 confirmed on Tuesday that the prime minister has the controversial feature turned on, but insisted Sir Keir uses it in line with guidance stating that it is permitted as long as it “does not impact record keeping or transparency responsibilities”.But the admission has raised questions about how many messages between Sir Keir and the former Labour peer may be missing from the latest tranche of the Mandelson files, released on Monday.The Prime Minister told broadcasters: “Let me assure you I have complied with the Humble Address.“All the messages I hold have been passed over. I went through the same process as everybody else.“And many people, not just in politics, use disappearing messages.”Sir Keir sacked Lord Mandelson in September 2025 after leaked emails which showed the peer sent supportive messages even as Jeffrey Epstein faced jail for sex offences (PA Wire)WhatsApp allows users to set messages to automatically vanish after 24 hours, 7 days, or 90 days, meaning past exchanges between the prime minister and Lord Mandelson would now be unrecoverable.Sir Keir sacked Lord Mandelson in September 2025 after leaked emails which showed the peer sent supportive messages even as Jeffrey Epstein faced jail for sex offences.MPs voted earlier this year to force the disclosure of documents relating to his time as ambassador.The Prime Minister chaired a meeting of his Cabinet on Tuesday morning after the latest document dump laid bare splits within Labour.Monday’s release included records of WhatsApp exchanges between Lord Mandelson and Cabinet minister Pat McFadden that revealed the latter’s frustration with his colleagues.In May 2025, in the wake of local election setbacks and the Runcorn by-election defeat, Mr McFadden said: “Lot of manoeuvring here this week. Angela (Rayner), Gordon (Brown). Doesn’t feel good for Keir.”Lord Mandelson was highly critical of Sir Keir’s operation in messages, saying the Prime Minister ‘lacks verve’ and that Chancellor Rachel Reeves could not explain where economic growth would come from (Sky News)He also complained that Labour MPs were “asking the wrong questions”.“Every meeting I have is ‘who can we tax in order to pay benefits to others’,” said Mr McFadden, who became the Work and Pensions Secretary, responsible for the welfare system, in September 2025.Lord Mandelson was highly critical of Sir Keir’s operation in messages, saying the Prime Minister “lacks verve” and that Chancellor Rachel Reeves could not explain where economic growth would come from.MPs will have the opportunity to debate the second tranche of files on Wednesday.