Labour MP slams Kemi Badenoch’s ‘wild accusations’ as Keir Starmer fights for future amid Lord Mandelson row

"That is not true, and the Prime Minister will set out why that's not true when he speaks at the dispatch box of the House of Commons just behind me this afternoon."

The row centres on the appointment of Peter Mandelson as US Ambassador, with Tory leader Kemi Badenoch accusing the Prime Minister of lying about what he did or didn't know.

Sir Keir will deliver an address to MPs this afternoon at the dispatch box, clarifying exactly what he knew about the disgraced peer's vetting process.

Mr Alexander explained that the controversy stems from a failure within the Foreign, Commonwealth and Development Office to pass on crucial vetting information to senior ministers.

He told GB News: "The fact is, there was information in relation to deep vetting that was withheld both from the Foreign Secretary and from the Prime Minister.

"And he will account for that and explain that breakdown in process when he speaks to the House of Commons."

The Scottish Secretary argued that accepting the Conservative claims would require believing that all ministers involved in Lord Mandelson's appointment, numerous senior civil servants, and associates of former Foreign Office Under-Secretary Olly Robbins had participated in a coordinated deception.

According to Mr Alexander, the Prime Minister was informed of the withheld information on Tuesday evening by the Permanent Secretary in the Cabinet Office.

The Scottish Secretary confirmed that the Cabinet Secretary attended this initial briefing, with the Prime Minister's Principal Private Secretary also present to take an official minute of the discussion.

Mr Alexander stated: "In that very meeting, the Prime Minister made clear that he wanted to return to Parliament to set the record clear in terms of what he knew and what he did not know, but that he required the facts in order to be able to do so."

Mr Alexander pointed to what he described as a growing agreement among key figures that the FCDO failed to share information and did not follow vetting agency recommendations.

"That's now an established matter of fact," he said, noting this consensus includes allies of Olly Robbins, the Cabinet Secretary, the Permanent Secretary in the Cabinet Office, and all ministers involved in the decision.

The Scottish Secretary defended the Prime Minister's approach of gathering evidence before addressing MPs, arguing that Parliament deserves facts rather than mere allegations.

He added: "One of the reasons that there is such concern over this controversy is that information was not only not provided to ministers, information therefore was withheld from Parliament."

Ahead of the address to the House of Commons today, Mrs Badenoch has penned a letter to the Prime Minister, branding him "recklessly negligent" and "dishonest".

In the letter to Sir Keir, she said: "This has been a tawdry and shaming affair for you and your party, and for this country.

"Not only have you damaged our relationship with the United States and insulted the victims of the paedophile Jeffrey Epstein, but you have also undermined our national security by giving the highest diplomatic post to an individual that the security services found to be of 'high concern'.

"Instead of another round of blaming everyone else and demeaning the office of Prime Minister, I trust we can look forward to a frank statement in which you will take due responsibility."