The Cabinet Office will not release a key document linking to Peter Mandelson’s vetting following police warnings that it could derail the ongoing investigation into the disgraced peer.

Government officials will not release the summary document, complied by the UK Security Vetting Agency (UKSV), following advice from Scotland Yard that it could jeopordise prosecuting Mandelson in future.

The nine-page summary, which was pulled together before Mandelson’s appointment as british ambassador to the US, was due to be included in the second batch of files relating to the disgraced former politician which was scheduled to be released next week.

However, a spokesperson for the Metropolitan Police said some documents should not be made public, according to the Times.

“An investigation into alleged misconduct in public office is under way and it is vital due process is followed so that our criminal investigation and any potential prosecution is not compromised,” they said.

The spokesperson added that the police force “are working with the Cabinet Office to review relevant documents provided to us by them.”

“While complying with the Humble Address is a matter for government and parliament, we have asked the Cabinet Office not to make some documents public as they would have a detrimental impact on our investigation or any subsequent prosecution,” they said.

Mandelson saga continues

Arrested in February, Mandelson is still under active investigation after leaked emails suggested he shared sensitive government secrets with Jeffrey Epstein while serving under Gordon Brown’s government.

At the beginning of the month, the Cabinet Office said the intelligence and security committee (ISC) had mutually agreed to redact parts of the summary so it could be published as part of the Mandelson files.

In April, top civil servant in the foreign office, Sir Olly Robbins, was ousted after it had emerged the disgraced peer was denied clearance in a confidential security vetting process.

This follows Mandelson in March demanding a £547,201 payout for the remainder of his time as UK ambassador to the US after being sacked, according to official documents.