MPs must urgently probe the activities of the Labour Together faction in the wake of the Mandelson scandal, the Labour left is urging.

Campaign organisation Momentum said that “there must be a fully independent parliamentary inquiry into Mandelson’s appointment and the scandals surrounding Labour Together.”

And left MP Apsana Begum said that Labour Together, for long run by sacked Downing Street chief of staff Morgan McSweeney and later by sacked Cabinet Office minister Josh Simons, was at the heart of the disastrous appointment of Peter Mandelson as ambassador to the US.

“One particular faction within the Labour Party and their interests remain at the centre of all of this, who are embroiled in the Labour Together scandal,” she said.

“We need an independent investigation into Labour Together.”

And John McDonnell MP said that PM Sir Keir Starmer had allowed Labour “to be dragged into the gutter by Mandelson, McSweeney, Simons and Labour Together.”

The calls came as the disgraced peer was evicted from the Privy Council, meaning King Charles will have to get along without advice from the boon companion of paedophile financier Jeffrey Epstein.

Minutes of a meeting of the council this week include “an order striking out The Lord Mandelson from the List of Members of His Majesty’s Most Honourable Privy Council.”

Mr Mandelson has already resigned from the Labour Party and the House of Lords and has been arrested by police on suspicion of misconduct in public office.

He denies any criminality or acting for financial again.

Mr Mandelson now faces growing calls to either return or donate to charity the £75,000 “golden goodbye” he received from the government after being fired as ambassador in Washington last September.

Minister Nick Thomas-Symonds told Sky News that he shared the “moral outrage” over the payment, which the government claims was necessary to avoid an unseemly and expensive dispute in an Employment Tribunal.

And Scottish Labour leader Anas Sarwar said: “This is a man who has proven to be a traitor to his country. He should do the right thing and return the money that he got as a payment.”

In his first public comment since the release of documents showing he overruled warnings to appoint Mr Mandelson, Sir Keir said “it was me that made the mistake and it’s me that makes the apology to the victims of Epstein.”

He denied there was any cover-up over the release of the papers, although many were held back by the police.

Legislation is now being prepared to formally strip Mr Mandelson of his title. Downing Street said today that it could be broadened to include other rule-breaking peers, not an exclusive club.

A spokesman said: “The prime minister has asked officials to draft legislation which allows Peter Mandelson’s peerage to be removed as quickly as possible.

“The government’s preference is to bring forward legislation that could be applied to any peer who has breached the rules.”