Revealed: Mandelson failed vetting but Foreign Office overruled decision

Peter Mandelson failed his security vetting clearance but the decision was overruled by the Foreign Office to ensure he could take up his post as ambassador to the US, an investigation by the Guardian can reveal.

According to multiple sources, Mandelson was initially denied clearance in late January 2025 after a developed vetting process, a highly confidential background check by security officials.

Keir Starmer had by then announced he would be making Mandelson the UK’s chief diplomat in Washington, posing a dilemma for officials at the Foreign Office, who decided to use a rarely used authority to override the recommendation from security officials.

Mandelson’s failure to secure vetting approval has not previously been publicly revealed, despite intense scrutiny over his appointment and the release by the government of 147 pages of documents supposed to shed light on the case.

Further documents are due to be released. However, it can also be revealed that senior government officials have been considering whether to withhold from parliament documents that would reveal that Mandelson was not given vetting approval from security officials.

The decision, which rests with the Cabinet Office, has not yet been taken. Any attempt to withhold the documents from the intelligence and security committee could amount to a breach of a parliamentary motion to release “all papers relating to Mandelson’s appointment”.

The revelation that the now former ambassador was not granted clearance by UK Security Vetting (UKSV), a division of the Cabinet Office that scrutinises the background of prospective civil servants, will raise further questions about the prime minister’s judgment in appointing him.

Starmer will also be pressed over whether he misled the public in remarks about the security vetting process, which he said had given Mandelson “clearance for the role”.

It is not known whether the prime minister was made aware that his pick for Washington ambassador had not been granted approval by UKSV, which conveys its decision as a recommendation to government departments. Neither is it known who in the Foreign Office made the decision to overrule UKSV.

Sir Olly Robbins, the current permanent secretary in the Foreign Office, was the department’s top civil servant in late January 2025 when the decision was made, having taken up the role earlier that month. The foreign secretary was David Lammy, who is now the deputy prime minister.

Starmer’s then chief of staff, Morgan McSweeney, who resigned in February over his role in appointing Mandelson, could also now be asked whether he had any involvement in, or knowledge or, the decision to overrule UKSV’s denial of clearance.

That decision was made weeks before Mandelson was due to take up his post in February 2025. Seven months later, he was sacked over his relationship with the convicted sex offender Jeffrey Epstein.

Ministers and officials are now likely to be pressed over whether they have been fully transparent about the process that led up to his appointment.

At a press conference in Hastings on 5 February, Starmer responded to a question from a journalist by saying there had been “security vetting, carried out independently by the security services, which is an intensive exercise that gave him [Mandelson] clearance for the role. You have to go through that before you take up the post.” He added: “Clearly both the due diligence and the security vetting need to be looked at again.”

This appeared to partly put the blame for Mandelson’s appointment on the failure of a vetting process which, according to sources, his government had overruled.

In the wake of Mandelson’s sacking as US ambassador on 11 September 2025, after the extent of his relationship with Epstein came to light, parliamentary scrutiny mounted. On 16 September, Yvette Cooper, the foreign secretary, and Robbins, her top official, responded to questions over the vetting process with a letter to the foreign affairs select committee.

“Peter Mandelson’s security vetting was conducted to the usual standard set for developed vetting in line with established Cabinet Office policy,” the letter said, explaining that the process had been undertaken by UKSV on behalf of the Foreign, Commonwealth and Development Office (FCDO).

Cooper and Robbins said the process had “concluded with DV clearance being granted by the FCDO in advance of Lord Mandelson taking up post in February”.

What the letter failed to inform parliament was that UKSV had denied Mandelson’s clearance – a recommendation that threatened Starmer having to withdraw a high-profile appointment he had already made public.

UKSV’s vetting decisions are almost always enforced by government departments, but they technically have the authority to override the recommendations. The precise reason that UKSV recommended that Mandelson not receive clearance is now likely to be subject to intense speculation.

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According to publicly available government documents, the UKSV developed vetting process includes a questionnaire and interviews requiring disclosure of highly private information, including about personal finances, business connections and sexual history.

It is understood that developed vetting, which is a requirement even for junior civil servants in the Foreign Office, almost always ends in approval, although there is sometimes a recommendation to manage risks. In some cases, approval is subject to mitigations. An outright denial, as in Mandelson’s case, is rare.

It is even more exceptional for a decision by UKSV to deny an applicant to then be overruled by a government department, although officials do have that power. The decision to do so in the case of Mandelson occurred over a 48-hour period in late January 2025.

A formal decision to deny him clearance was made by UKSV on 28 January 2025. According to sources, UKSV informed the Foreign Office that the risk factors involving Mandelson meant that his clearance should be denied.

Robbins was a few weeks into the role of permanent secretary at the time of the decision, and was Mandelson’s soon-to-be line manager, both of which suggest he would have been involved in the decision. A decision of that magnitude may also have warranted political approval, or at least consultation, which could have involved Lammy or Downing Street.