Peter Mandelson was granted access to some of the UK’s most sensitive intelligence despite failing the official security vetting required for the role, according to new revelations that have triggered a major political crisis.

The former ambassador to the United States was given the highest level of security clearance shortly after taking up the position in early 2025. This clearance allowed him to access top secret material that could put national security and intelligence sources at risk if compromised.

However, officials had previously concluded that Mandelson should not receive this level of clearance following concerns raised during the vetting process.

Vetting Overruled Behind Closed Doors

Despite that assessment, senior figures inside the Foreign Office intervened and approved his clearance anyway, arguing the risks could be managed.

The decision was taken without informing the Prime Minister at the time.

Keir Starmer only became aware of the failed vetting more than a year later, sparking outrage inside Downing Street and leading to the dismissal of a senior civil servant.

The episode has raised serious questions about who ultimately controls national security decisions and whether ministers are being kept in the dark by Whitehall officials.

Highest Level of Clearance

The level of clearance granted to Mandelson is reserved for individuals who need access to the most sensitive intelligence held by the state.

It involves extensive background checks and is designed to identify any vulnerabilities, conflicts of interest or potential exposure to foreign influence.

In Mandelson’s case, concerns had reportedly been raised about his links to controversial figures and international connections, though the full details of the vetting failure have not been made public.

Political Fallout Intensifies

The revelations have intensified pressure on Starmer, who had previously told Parliament that Mandelson had been properly vetted before taking up the role.

Downing Street has since acknowledged that this was not the case, with the Prime Minister insisting he was not informed of the failed vetting at the time.

The situation has triggered accusations of a breakdown between ministers and the civil service, with critics warning it represents one of the most serious failures of government oversight in recent years.

Growing Questions Over Accountability

The controversy has also reignited concerns about Mandelson’s past links and whether they should have disqualified him from holding such a sensitive position in the first place.

A wider review of the vetting process is now expected, with increasing pressure for transparency over how and why the original decision was overridden.

The scandal is likely to dominate Westminster in the coming days, with further scrutiny expected in Parliament as questions mount over accountability, national security and the role of senior civil servants.