Downing Street has set out how it intends to comply with Parliament’s instruction on papers relating to Lord Mandelson’s former appointment as Ambassador to the United States. In a letter dated 6 February 2026 to the Intelligence and Security Committee (ISC) chair, Lord Beamish, the Prime Minister acknowledges the Humble Address and commits to a structured process for disclosure. (assets.publishing.service.gov.uk)
The Prime Minister has asked the Cabinet Secretary to work with the ISC to agree how any material that could prejudice national security or international relations will be shared and reviewed, noting that this will be undertaken with regard to the Metropolitan Police’s ongoing investigation. He also notes the expectation that documents should be made available to Parliament “as soon as possible”, while recognising a very significant volume of material will require scoping before release. (assets.publishing.service.gov.uk)
The letter follows the House of Commons vote on 4 February 2026 to require the Government to lay before the House all papers concerning Mandelson’s appointment, with an amendment providing that any papers prejudicial to national security or international relations be referred instead to the ISC. The amended motion was agreed to without division and recorded in Hansard. (hansard.parliament.uk)
Under the Justice and Security Act 2013 framework, the ISC is the statutory body equipped to handle classified material and to produce reports first submitted to the Prime Minister for national security clearance prior to publication to Parliament. Lord Beamish currently serves as Chair, as confirmed by the Committee’s official membership page. (isc.independent.gov.uk)
The Commons resolution is expansive. It seeks Cabinet Office due diligence provided to No. 10, the conflict of interest form submitted to the Foreign, Commonwealth and Development Office, material supplied to UK Security Vetting, minutes of meetings around the appointment decision, relevant ministerial and official communications before and during Mandelson’s tenure, and details of any departure payments. (hansard.parliament.uk)
Operationally, departments should prepare for coordinated retrieval and classification review across No. 10, the Cabinet Office, the FCDO and UK Security Vetting. The Prime Minister’s letter signals that sensitive material will move through an ISC-managed channel and that the Metropolitan Police’s requirements will be considered to avoid prejudice to the criminal investigation. (assets.publishing.service.gov.uk)
Timing remains contingent on document identification and review. The Government states it wishes to meet Parliament’s instruction with “urgency and transparency”, but the anticipated volume and sensitivity mean staged handling is likely: direct laying of non-sensitive papers to the House, with sensitive material routed to the ISC for secure assessment. (assets.publishing.service.gov.uk)
For policy professionals, the key point is that the disclosure route now relies on an established statutory oversight body rather than ad hoc departmental redaction alone. The ISC’s mandate and practices-secure handling, consultation with the Prime Minister on national security redactions, and subsequent reporting-provide a path to balance transparency with protection of sensitive capabilities and external relationships. (isc.independent.gov.uk)