Sir Laurie Magnus CBE, the Independent Adviser on Ministerial Standards, has declined to open an investigation into the Prime Minister over the appointment of Peter Mandelson as His Majesty’s Ambassador to the United States. In a letter dated and published on 13 March 2026 to Alex Burghart MP, Shadow Chancellor of the Duchy of Lancaster, he said he did not see grounds to proceed and released the correspondence in the public interest. (gov.uk)
The response addresses Mr Burghart’s request of 12 March to examine two statements by the Prime Minister: a remark on 4 February 2026 that “if I knew then what I know now, he would never have been anywhere near government”, and a 10 September 2025 assertion that due process was followed for the appointment. (assets.publishing.service.gov.uk)
On the February statement, Sir Laurie records that the Prime Minister had acknowledged being aware at the time of appointment of Peter Mandelson’s past association with Jeffrey Epstein, including in an exchange in the House with Rt Hon Kemi Badenoch MP and by reference to a due‑diligence document released following a Humble Address. He considers the phrasing to relate instead to additional material contained in emails released by Bloomberg in September 2025, which the Prime Minister has said would have precluded the appointment had it been known earlier. (assets.publishing.service.gov.uk)
Turning to the September 2025 claim on process, the adviser states that, because this was a political rather than an official appointment, the government used the Direct Ministerial Appointment route provided for by section 10(3) of the Constitutional Reform and Governance Act 2010. He cites Cabinet Secretary advice of 11 November 2024-released under the same Humble Address-setting out steps to secure security clearances, conduct due diligence on potential conflicts and formalise the decision by ministerial letter to the FCDO Permanent Under‑Secretary. (assets.publishing.service.gov.uk)
Sir Laurie notes that his terms of reference concern the individual conduct of ministers and do not extend to investigating departmental actions or the government collectively. On that basis he does not address comments about the handling of the Humble Address, and concludes there is no basis to investigate the Prime Minister’s statements; the letter is therefore being published. (assets.publishing.service.gov.uk)
For policy practitioners, the correspondence clarifies that references to “due process” in such cases point to compliance with the statutory direct appointment mechanism rather than open Civil Service competition. Accountability for the choice of a political ambassador remains ministerial and to Parliament; the adviser’s oversight focuses on whether ministerial conduct, as opposed to departmental process, meets the standards set out for office. (assets.publishing.service.gov.uk)