The government is preparing to publish more documents about the appointment of Lord Mandelson as US ambassador.

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 Christmas. Some will still be withheld at the request of the Met.

Cat Little, permanent secretary at the Cabinet Office, said that some of the documents could “now be published without prejudicing their investigation”.

The Met Police had 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.

Writing to the chair of Parliament’s Intelligence and Security Committee, Little said: “The Cabinet Office is now beginning the process to prepare these documents so that they may be laid before the House in response to the humble address motion as soon as possible.”

She said the documents would be reviewed and in some instances may need to be redacted “for the purposes of avoiding prejudice to national security or international relations”.

The process is expected to be completed before Parliament rises for the Christmas recess on 17 December.

Lord Mandelson was arrested on 23 February on suspicion of misconduct in public office.

He has repeatedly let it be known that he believes he has not acted criminally, did not act for personal gain and is cooperating with the police.

“Our investigation into alleged misconduct in public office is ongoing,” the Met Police said in a statement.

The lifelong Labour politician became the British ambassador to the US in February 2025, but was sacked in September after Downing Street said new information about the extent of his relationship with Epstein had emerged.

After his sacking, the government – then led by Sir Keir Starmer – was heavily criticised for giving Lord Mandelson the job and in February MPs voted to force the government to publish papers relating to his appointment.

Mike Wood, shadow Cabinet Office minister, said: “We still haven’t got to the bottom of the Mandelson scandal.

“Labour did their utmost to hold this information back and it was only released because of the Conservatives humble address.”

Sign up for our Politics Essential newsletter to keep up with the inner workings of Westminster and beyond.