Question to the Cabinet Office:

To ask the Minister for the Cabinet Office, what role the Cabinet Office played in setting or overseeing the processes for security vetting and appointment of Lord Mandelson as UK ambassador to the United States; and whether the Cabinet Office provided guidance on the use of informal communications such as WhatsApp by ministers and officials involved in that process.

The Cabinet Office carried out a due diligence exercise prior to the announcement of Lord Mandelson’s role as His Majesty's Ambassador to the United States as documented in the response to the Humble Address published on 11 March 2026.

The Cabinet Office has responsibility for security vetting policy and the UK Security Vetting (UKSV) organisation is based in the Cabinet Office. UKSV carried out the national security vetting for Lord Mandelson in January 2025, although the Foreign, Commonwealth and Development Office sponsored this clearance and made the decision. The Cabinet Office officials involvement in the security vetting process is documented in the second Humble Address tranche published in the House on 1 June 2026.

Central guidance was issued in 2023 on Using Non-Corporate Communication Channels for Government Business, which is available on GOV.UK.