The Cabinet Office has referred how Peter Mandelson handled sensitive government information while he was a minister to the police.
Officials have handed over an assessment of how they think Lord Mandelson broke strict information handling procedures.
An initial review by the Cabinet Office of documents released by the US Department of Justice has found that emails sent by Lord Mandelson to the paedophile financier Jeffrey Epstein likely contain market sensitive information relating to the 2008 crash and official activities thereafter to stabilise the economy.
Paste BN understands that the Cabinet Office's referral to the police was made today.
The prime minister's official spokesperson said they were cooperating fully with the police and ready to assist them in any way needed.
The police are reviewing information, before deciding whether to launch an official investigation.
The Metropolitan Police last night said it was aware of the latest release of files related to Epstein and that it had received "a number of reports relating to alleged misconduct in a public office".
That came after emails appeared to show conversations between Mandelson and Epstein about government and political matters while the former was serving as business secretary and the de-facto deputy prime in Gordon Brown's government.
Mandelson has previously said: "I was wrong to believe Epstein following his conviction and to continue my association with him afterwards. I apologise unequivocally for doing so to the women and girls who suffered."
In an interview with The Times carried out last week but published on Monday, Mandelson referred to a "handful of misguided historical emails, which I deeply regret sending", and described Epstein as "muck that you can't get off your shoe".