A second tranche of files relating to Lord Mandelson's controversial appointment as ambassador to Washington will be released today despite police requests to withhold key documents.
The Metropolitan Police has intervened to request that certain documents remain private, warning that their publication could undermine its ongoing criminal investigation into ex-Labour peer.
Scotland Yard confirmed on Sunday it had asked the Cabinet Office "not to make some documents public as they would have a detrimental impact" on its inquiry and any potential prosecution.
Three sources familiar with the process told the BBC that more than 1,000 documents are expected to be released on Monday.
Among the files reportedly set to be withheld is a nine-page summary of Lord Mandelson's security vetting process, meaning the full extent of concerns raised by security officials may never become public.
It emerged last month that Lord Mandelson failed the developed vetting process conducted by UK Security Vetting, which recommended against granting him clearance following criminal, financial and security service checks.
Despite that recommendation, the Foreign Office's most senior official overruled the decision, allowing Lord Mandelson access to top-secret briefings and other highly sensitive material required for the Washington posting.
The documents are understood to contain no record of measures taken to mitigate security concerns surrounding the Labour peer's appointment.
Among the files reportedly set to be withheld is a nine-page summary of Lord Mandelson's security vetting process
|GETTY
Sir John Hayes raised the issue in the Commons earlier this month, asking Darren Jones whether any documents existed detailing risk mitigation measures linked to the appointment.
Mr Jones replied: "All documents that are in the scope of the humble address will be published in the normal way."
MPs voted in February to force the Government to release all papers connected to the appointment through a humble address motion, despite ministers initially resisting publication on national security and diplomatic grounds.
Documents released in the first tranche in March revealed Sir Keir Starmer had been warned Lord Mandelson's association with Jeffrey Epstein posed a "general reputational risk" before the appointment was approved.
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Scotland Yard confirmed on Sunday it had asked the Cabinet Office 'not to make some documents public'
| PASir Keir's national security adviser, Jonathan Powell, is said to have described the appointment as "weirdly rushed".
Lord Mandelson was dismissed from the ambassadorial role in September 2025 after emails emerged showing he had encouraged Epstein to "fight for early release".
Documents later released in the US appeared to indicate the Labour peer shared confidential, market-sensitive government papers with the convicted sex offender while serving as Business Secretary.
In February, Lord Mandelson was arrested on suspicion of misconduct in public office and released on bail while the investigation continues.
Documents released in the first tranche revealed the PM was warned Lord Mandelson's association with Jeffrey Epstein posed a 'general reputational risk'
| PAHe has consistently denied any criminal wrongdoing and insists he did not act for personal gain.
Lord Mandelson has described his friendship with Epstein as a "terrible mistake" but maintained he "never saw anything in [Epstein's] life... that would give me any reason to suspect what this evil monster was doing".
The release of the second batch of documents comes just days after ministers were accused of attempting to withhold messages with the ex-Labour peer from Parliament.
Following the Conservative's' Humble Address back in February, Government officials of all levels, from ministers to mandarins, were required to give up their private correspondence with the New Labour titan.
But, when top politicians were approached to disclose the information, it was said ministers were hesitant to relinquish their grasp on the texts.
After ministers allegedly refused to hand over the messages, the Cabinet Office is said to have been forced to ask twice for the communications, insider sources told The Telegraph.
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