The Metropolitan Police says it has asked the government not to release certain documents at this moment that could undermine its investigation into Peter Mandelson.

The force announced yesterday that it was probing allegations that Lord Mandelson leaked market sensitive information from Downing Street to Jeffrey Epstein.

That came after emails, released as part of the latest tranche of Epstein documents published by the US Justice Department, appeared to show conversations between the pair about political matters while Mandelson was serving as business secretary and the de-facto deputy prime minister in 2009, in Gordon Brown’s government.

MPs are currently debating whether to release government documents relating to Mandelson’s appointment as the UK’s ambassador to the US last year – a job he was sacked from in September over his links to Epstein.

It comes amid pressure over whether the government knew about Mandelson’s continued relationship with the paedophile financier following his 2008 conviction for sex offences.

But Commander Ella Marriott, of the Metropolitan Police, said: “As with any investigation, securing and preserving any potential evidence is vital. 

“For this reason, when approached by the UK government today with their intent to publish material, we reviewed it immediately and advised that the release of specific documents could undermine our current investigation. 

“We therefore asked them not to release certain documents at this time. 

“Going forward, as material is made available to us, and if we identify further documents that we believe could prejudice our investigation, we will continue to ask the government to pause their release until such time as the risk of prejudice no longer exists. 

“The integrity of our investigation is paramount to securing justice. We are grateful for their cooperation. 

“We continue to assess all relevant information brought to our attention as part of this investigation.”

Yesterday, the force announced it had launched an investigation into a 72-year-old man, a former government minister, for misconduct in public office offences.