MPs accuse Starmer of withholding documents in Mandelson ambassador probe
Sir Keir Starmer has been accused by a parliamentary watchdog of withholding official documents from a long-running investigation into Peter Mandelson’s appointment as United States ambassador, after a leaked vetting file was held back and the government was found to be applying redactions “far too broadly”.
Redactions under fire
The Intelligence and Security Committee (ISC), which is overseeing the release of the material, has raised concerns that ministers are blacking out details in documents beyond what was originally agreed, particularly when it comes to personal information. The committee said it had “made clear that, in its view, they are being applied far too broadly” and noted that no independent body had been commissioned to review whether the redactions remained within the spirit of the parliamentary order that compelled their release.
That order, known as a Humble Address, was passed by MPs in February 2026 and required the government to hand over all files relating to Lord Mandelson’s appointment. The arcane procedure – effectively a petition to the monarch to extract information from the executive – is understood to be binding on the House once voted through. An amendment to the motion allowed documents that could compromise international relations or national security to be provided instead to the ISC, but the government later said it could also black out details deemed “commercially sensitive”, as well as individuals’ addresses and contact details.
The committee has rejected this broadening of the exemption, arguing that the terms of the Humble Address do not permit any documents to be withheld from Parliament without explicit permission. In a statement on Friday, it insisted that “while government may believe that there is good reason to withhold certain documents, it does not currently have the authority to so do”. It has therefore advised ministers to return to Westminster and formally seek Parliament’s agreement before keeping any papers back.
Vetting file withheld
The most significant document at the centre of the dispute is a vetting file held by UK Security Vetting (UKSV). The ISC has been told that this file – which reportedly relates to Mandelson’s failed developed vetting (DV) clearance – is being withheld from the disclosure process entirely. Mandelson was publicly appointed ambassador on 20 December 2024, but UKSV recommended denying him clearance in January 2025. Foreign Office officials overruled that decision on 29 January, granting him security clearance before he took up the post. Sir Keir has since said he was unaware of the failure until recently, describing the situation as “staggering” and blaming former Foreign Office chief Sir Olly Robbins for not informing him.
The first tranche of documents related to Mandelson’s appointment and subsequent dismissal was released on 11 March 2026. A second tranche is expected, with the ISC due to announce further files as early as next week. The committee has made clear it does not accept that the Humble Address allows for any documents to be withheld without Parliament’s explicit consent.
Mandelson was sacked in September 2025 following revelations about his relationship with convicted sex offender Jeffrey Epstein. In February 2026, Starmer said Mandelson had “betrayed our country, our Parliament, and my party” due to his association with Epstein and alleged leaking of market-sensitive information during the 2008 financial crisis. The Cabinet Office has forwarded emails between Mandelson and Epstein to the Metropolitan Police, who are conducting a criminal investigation. Mandelson resigned from the Labour Party and the House of Lords in March 2026.
Concerns over security and communications
Beyond the specific row over the Mandelson files, the ISC has raised “grave concerns” about a series of broader security failings exposed by the documentation. It found it “extraordinary” to see how much government business was being conducted over unofficial systems, citing lengthy WhatsApp conversations between senior officials and ministers as the format by which policy was being formulated. “Government systems exist for a reason and should be the proper forum for the conduct of government business,” the committee said. It noted that it had raised the issue with the previous government and was disappointed not only that it continued but that the practice had spread.
The committee also expressed alarm at the use of “lower level government IT systems” rather than more secure alternatives, warning that this failure “puts the UK’s national security at risk”. Reports indicate that 58 critical government IT systems assessed in 2024 had significant gaps in cyber resilience, and the government is unaware of the vulnerability of at least 228 ‘legacy’ systems. Cyber attacks have been identified by ministers as a top national security threat.
Finally, the ISC criticised the “lack of an audit trail” being kept across government, particularly within the Foreign Office – including agendas, minutes and records of conversations – and pointed to a “failure to adhere to security advice”. “Even when proper security processes have been followed, there appears to be nothing to say that the conclusions should be acted on,” the committee warned.
