Ministers have been warned not to follow Wes Streeting and publish their messages with Peter Mandelson amid a police investigation into alleged misconduct in a public office, it is understood.
In a message on Monday night, the Cabinet Office said members of Government should not release material that could be covered by a motion passed in Parliament last week.
Meanwhile, Scotland Yard warned on Tuesday that it was “vital due process is followed” so as not to compromise its probe.
It comes after the Health Secretary, seen by some as a protege of Lord Mandelson, shared a transcript of messages between himself and the former Labour grandee as he sought to distance himself from the peer.
Among the exchanges were concerns expressed by Mr Streeting that the Government had “no growth strategy” and that he would be “toast” at the next general election.
In a statement on Tuesday, a Metropolitan Police spokesperson said: “As part of our inquiries, we will review material identified and provided to us by the Cabinet Office to assess whether publication is likely to have a detrimental impact on our investigation or any subsequent prosecution.
“We will work alongside the Cabinet Office to review relevant documents over the weeks ahead. The process to decide which documents should ultimately be published remains a matter for Government and Parliament. “As we have stated previously, this investigation may be complex but we are focused on a timely and thorough process so that justice is served in this case, or future ones linked to the Epstein files.”
Mr Streeting’s association with Lord Mandelson has been regarded by some in Westminster as a possible hurdle, should he seek to succeed Sir Keir Starmer as Labour leader.
Speaking to Sky News’ Electoral Dysfunction podcast, he said he had shared the messages after a weekend of “smear and innuendo” suggesting he had something to hide.
Government figures are preparing to hand over reams of material to Parliament’s security watchdog as they face pressure to reveal the extent of what was known about the peer’s friendship with Jeffrey Epstein when he was picked for the Washington job last year.
Sir Keir Starmer warned on Friday a “very significant volume of material” – understood to be likely to run into the high tens of thousands – would need to be reviewed. Following a Commons motion, Downing Street agreed to release all documents relating to Lord Mandelson’s appointment, including messages between ministers and senior officials that have the potential to prove embarrassing for the Government.
Control over which files can be released into the public domain has been ceded to Parliament’s Intelligence and Security Committee (ISC) after a Labour backlash to No 10’s initial attempt to add possible exemptions to protect international relations.
Committee chairman Lord Beamish said the ISC would not “do anything which would undermine” the police investigation following accusations Lord Mandelson passed market-sensitive information to Epstein when he was business secretary following the 2008 financial crisis.
Sir Keir believes the files will prove the former Labour grandee lied about the extent of his ties to the paedophile financier during his vetting for the UK’s top diplomatic posting abroad.
The Prime Minister has apologised for his decision to appoint Lord Mandelson but vowed to stay in No 10 to fulfil “my mandate and my responsibility to my country” after surviving renewed calls for his resignation from members of his party, including Scottish Labour leader Anas Sarwar.
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