Six of the most important revelations from the grilling of ex-Foreign Office boss

Therefore, Sir Keir sacked Sir Olly, claiming that the security vetting outcome was “information that [he] should have had”, vowing that he did not mislead Parliament over the appointment.

Below, GB News outlines the key highlights of the session:

No10 exerted 'constant pressure' on Foreign Office 

Sir Olly illustrated an “atmosphere of constant chasing” over the appointment, where the Foreign Office was under significant pressure to rubber-stamp the post.

Emily Thornberry, chair of the Foreign Affairs Select Committee, pressed the ex-Foreign Office boss to provide details on how No10 was exerting said pressure and the impact that had on the civil service’s ability to do their job.

Whilst Sir Olly dug his heels in, saying he would not name names, he did say it was between “private office to private office”, indicating No10 was responsible for the “constant pressure”.

Despite this, he said that he and his team followed due process with the appointment, sharing he had “no regrets” about his “brilliant people” and the judgement to which they came.

Sir Olly 'regretted' Prime Minister did not change course after due diligence report findings 

Sir Olly said it was a “red herring” to focus on who was told about the outcome of the vetting findings.

He argued the Prime Minister was already aware of Lord Mandelson’s various red flags as this would have been highlighted in the due diligence process.

The ex-Mandarin said he “regretted” the due diligence report on the now-disgraced peer “did not colour the Prime Minister’s judgement” of his unsuitability for the role as UK ambassador to the US.

He emphasised that No10 clearly were not interested in any civil service processes around political appointments, describing it as a “dismissive approach”.

Sir Olly also claimed the Cabinet Office insisted Lord Mandelson did not need vetting and highlighted the announcement was made before the security screening had been carried out.

Sir Keir requested ambassadorial role for disgraced Lord Matthew Doyle 

A slight departure from the focus on Lord Mandelson, Sir Olly revealed No10 pressured him to find an ambassadorial role for Lord Matthew Doyle, Keir Starmer's then-director of communications.

The ex-Mandarin claimed he was instructed by Sir Keir to keep it secret from the Foreign Secretary, a situation he described as "uncomfortable".

He said he struggled to justify handing a senior diplomatic posting to Lord Doyle, after he was found to have campaigned for a paedophile, Sean Morton.

Sir Olly said it risked driving experienced career diplomats out of the Foreign Office and ultimately he pushed back, telling No10 it would be "very hard for me personally to defend”.

Lord Mandelson's relationship with paedophile Jeffrey Epstein NOT reason for vetting denial 

Peter Mandelson’s security vetting findings were not based on his relationship with Jeffrey Epstein, Sir Olly confessed.

The findings of any developed vetting procedure are strictly confidential, therefore unlikely to ever be published, but the ex-Mandarin did say they were centred on his friendship with the now-dead paedophile financier.

Whilst the content is not known, there is speculation that it was centred on Lord Mandelson’s various dealings with Russia and China.

This comes after it was revealed that a Chinese biotech firm, on America's to-watch list, was Lord Mandelson's largest client.

Sir Olly contested Prime Minister's claim he would of blocked Lord Mandelson appointment if was aware of vetting outcome

Sir Olly contested Sir Keir's claims that he would have blocked Lord Mandelson’s appointment if he was aware of the vetting recommendations.

The Prime Minister told MPs in the Commons on Monday that he “would not have gone ahead with the appointment" had he known about UK Security Vetting's (UKSV) findings.

However, the ex-Foreign Office boss said it would have been “very difficult” given the role had already been announced and could have “damaged US-UK relations”.

He also said that Lord Mandelson had received a contract of employment and a posting letter to Washington had been sent within hours of the appointment decision.

Sir Olly claimed he did not see vetting documents himself 

After Lord Mandelson was sacked as US ambassador, Sir Olly requested the full vetting documents but was denied access following discussions between the Foreign Office and Cabinet Office on national security grounds.

The vetting team had reportedly "ticked the red box", an explicit recommendation not to approve Mandelson, yet the ex-Foreign Office boss said he was never shown that conclusion.

Instead, he recalled being told the case was "borderline" and that UKSV were "leaning towards recommending against" with assurances that the risks could be mitigated.

Therefore, at the time, he suggested the Foreign Office "might wish to grant clearance with appropriate risk management".

In the closing remarks, after an explosive two and half hours of grilling, Sir Olly gave an emotional speech about his role in the Foreign Office.

He said: "As a human being I’m desperately, desperately sad about it.

"I love that job, I love that institution, I was proud to serve this Government and any government that might follow it."

He gave his adoration for his colleagues within the Foreign Office, expressing he will miss them greatly.

Sir Olly alluded that there might be legal proceedings over his sacking, saying he did not "fully understand" Sir Keir's decision to give him the boot.