A senior minister has defended Sir Keir Starmer's handling of Lord Mandelson's appointment as US ambassador despite acknowledging it caused "damage" to the government.

Cabinet Office minister Nick Thomas-Symonds told the BBC Sir Keir "accepted making a mistake" but had responded by trying to make reforms to the "very structures of power in our society".

Documents released by the government showed Sir Keir was warned the peer's relationship with Jeffrey Epstein posed a "reputational risk" before he was confirmed as US ambassador.

Conservative Party leader Kemi Badenoch has said Labour MPs should consider whether Sir Keir is "fit to run our country" after being "dishonest" about what he knew.

Sir Keir is expected to face questions about Lord Mandelson when he speaks to journalists during a visit to Belfast.

He has previously said he did not know the extent and depth of the pair's relationship when Lord Mandelson was appointed in December 2024.

The peer began the ambassadorial role in February 2025 but was sacked in September after Downing Street said new information about the depth of his relationship with Epstein had emerged.

The newly-released documents show advice sent to the prime minister said Lord Mandelson and Epstein's relationship continued after the financier's conviction for procuring an underage girl in 2008.

A due diligence document sent to the PM on 11 December 2024 - nine days before he was confirmed as ambassador - raised a number of issues which could pose a "reputational risk".

It highlighted a 2019 report commissioned by US bank JP Morgan which found Epstein appeared to "maintain a particularly close relationship" with Lord Mandelson.

The document notes that the peer reportedly stayed in Epstein's house while the financier was in jail in June 2009.

Thomas-Symonds told BBC Radio 4's Today programme that the document "prompted the prime minister to seek assurances, to ask questions".

The initial batch of documents released by the government does not include a series of follow-up questions that Number 10 sent to Lord Mandelson about his relationship with Epstein.

Police asked Downing Street not to publish the exchanges yet to avoid prejudicing their ongoing investigation.

Pressed on concerns about the suitability of Lord Mandelson for the role and warnings of reputational risk, Thomas-Symonds replied: "Previous Labour prime ministers have also taken a chance on appointing Peter Mandelson to particular roles."

He said Sir Keir has not sought to move on from the issue but instead is "understanding the damage that it has done and then putting in place changes to public life, to the very structures of power in our society … that have ignored what has happened to women and girls at the hands of powerful men".

The documents suggested Lord Mandelson was offered briefings about sensitive material from the Foreign Office before the department had finished the formal vetting process.

An email from the US and Canada department of the Foreign Office on 23 December 2024 informed Lord Mandelson he would be briefed further in person from 6 January 2025 onwards "including at higher tiers".

The peer's offer of employment on 30 January last year confirmed his developed vetting clearance.

An email on 4 February to Lord Mandelson from the department noted the role also required a higher level of vetting, known as Strap clearance, and a new application would need to be submitted to receive it.

Conservative shadow chancellor of the Duchy of Lancaster Alex Burghart said: "Allowing a scandal-ridden former minister access to highly-sensitive information before proper clearance is completely careless."

The government has said it will review the national security vetting system, including seeking to improve the due diligence process and not announcing diplomatic appointments until security vetting has been completed.

Lord Mandelson remains of the view that he did not lie to the prime minister, does not recall being asked questions about Epstein face-to-face during vetting interviews and answered written questions about his contact with the sex offender after his conviction truthfully and fully.

The peer has long argued that he accepted Epstein and his lawyer's version of events and only discovered the truth after his death in 2019.

He resigned from the Labour Party in February and was arrested on suspicion of misconduct in public office weeks later, over allegations he had passed market-sensitive government information to Epstein when he was a minister.

He remains under police investigation but his bail conditions were lifted last week.

Lord Mandelson has repeatedly let it be known that he believes he has not acted criminally, did not act for personal gain and is cooperating with the police.

Modelling agent used businesses to recruit girls and arrange US visas to visit Jeffrey Epstein, Brazilian women tell BBC.

Documents also suggest the peer explored the possibility of a £500,000 severance payment after being sacked as US ambassador.

Richard Kahn and Darren Indyke administer Epstein’s estate - court filings allege complicity in his crimes.

She had been patron of human rights organisation Anti-Slavery International for seven years.

Andrew Mountbatten-Windsor was arrested on suspicion of misconduct in public office last month.