Sir Keir Starmer’s administration faced a sharp rebuke on Thursday when the House of Commons Intelligence and Security Committee (ISC) accused it of concealing vital documents related to former Labour minister Peter Mandelson’s US ambassadorial appointment. the committee said the government also routinely uses unsecured messaging apps for policy decisions, raising fresh security concerns.

Missing Mandelson vetting file sparks ISC alarm

The ISC highlighted that the critical vetting dossier compiled by the UK Security Vetting (UKSV) unit of the Cabinet Office has not been produced. According to the committee, the file contains the “controversial vetting papers” that would clarify why Mandelson , a peer under scrutiny, was cleared for a senior diplomatic post.

Without the dossier, the ISC argues that Parliament cannot assess whether proper security standards were applied, a gap that “puts the UK’s national security at risk,” the report states.

WhatsApp policy talks reveal audit‑trail gaps in Number 10

Long‑form WhatsApp conversations among senior ministers and officials were cited as the primary medium for shaping policy, a practice the ISC deems “extraordinary” for a government office. The committee noted that these chats lack the audit trails required for secure record‑keeping.

“There is a systemic failure to retain agendas, minutes, and records of conversations, especially within the Foreign, Commonwealth & Development Office (FCDO),” the ISC warned, underscoring a broader cultural issue of informal communications supplanting formal channels.

ISC warns of national‑security risk from unsecured communications

Beyond the missing Mandelson files, the ISC expressed “grave concern” over the reliance on insecure IT systems. it cited examples where ministers formulated policy over WhatsApp, a platform not vetted for classified information .

According to the watchdog, this pattern of behaviour could expose sensitive diplomatic negotiations to cyber‑espionage, a risk that “cannot be ignored” as the UK navigates a volatile global security environment.

Who holds the missing documents? Cabinet Office’s UKSV under scrutiny

The responsibility for the absent vetting file rests with the UKSV, part of the Cabinet Office tasked with deep‑level security checks. The ISC’s report suggests that the unit either failed to preserve the file or is unwilling to share it with Parliament.

“The lack of an audit trail in terms of agendas, minutes and records of conversations in the FCDO does not appear to be kept as a matter of practice,” the committee said, calling for an independent review of record‑keeping protocols.

Open question: Will the government release the full Mandelson dossier?

The ISC’s demand for the missing papers remains unanswered, and the government has not indicated a timeline for compliance. Additionally, it is unclear whether the Prime Minister’s office will overhaul its communications policy in response to the committee’s findings.