The government is preparing to publish more documents about the appointment of Lord Mandelson as British ambassador to the United States, with the new papers expected to be released before Christmas.

Batches of papers were published in March and June, but others were withheld because they were part of a Metropolitan Police investigation. The Cabinet Office has now said a number of extra documents will be published, likely before Parliament rises for the Christmas recess on 17 December.

Cat Little, permanent secretary at the Cabinet Office, said some documents could "now be published without prejudicing their investigation". Writing to Lord Beamish, the Labour peer who chairs Parliament's Intelligence and Security Committee, she said the Cabinet Office was preparing the documents to be laid before the House in response to the humble address motion as soon as possible.

Some documents still withheld

Some papers will still be held back at the Metropolitan Police's request, and documents may need redacting to avoid prejudicing national security or international relations.

More than 1,500 pages of documents have already been released under the humble address motion passed by MPs in February, which forced the disclosure.

The investigation behind the delay

The Metropolitan Police launched an investigation over allegations that, while he was serving as a government minister, Lord Mandelson had passed on market-sensitive government information to the late convicted sex offender Jeffrey Epstein.

Lord Mandelson was arrested on 23 February on suspicion of misconduct in public office. He became British ambassador to the US in February 2025 but was sacked in September after Downing Street said new information had come to light. The Met has said its investigation into alleged misconduct in public office is ongoing.

Sources: BBC News, More Mandelson papers to be published before Christmas, 5 November 2026; The Independent, Mandelson papers to be published before Christmas, 5 November 2026.