The prime minister's former chief of staff Morgan McSweeney will give evidence to MPs on the Foreign Affairs Committee next week about his role in the security vetting of Lord Mandelson.

McSweeney, who advised the prime minister to appoint Lord Mandelson as the UK's ambassador to the US, is likely to face questions about whether he put pressure on civil servants to speed up the vetting.

It comes after former senior Foreign Office civil servant Sir Olly Robbins accused No 10 of a "dismissive" attitude towards the process - a claim Downing Street has denied.

Cat Little, the most senior civil servant at the Cabinet Office, will appear before the committee on Thursday.

Last week, Little told Sir Keir Starmer that the UK Security and Vetting (UKSV) team had raised concerns about Lord Mandelson, but the Foreign Office had still granted him security clearance.

Committee chair Dame Emily Thornberry has said the Foreign Office's Chief Property and Security Officer Ian Collard and former Foreign Office top civil servant Sir Philip Barton have also been asked to give evidence.

The prime minister effectively sacked Sir Olly last week, expressing anger that the Foreign Office had not told him that Lord Mandelson failed security vetting.

Giving his version of events to the Foreign Affairs Committee on Tuesday, Sir Olly said he had not seen UKSV documents but had, in an oral briefing, been told that Lord Mandelson's case was "borderline" and the risks could potentially be managed.

He added that under civil service guidance he would not have been allowed to tell the prime minister about details of the vetting, only his final decision on the case.

Sir Olly also said that his department faced "an atmosphere of pressure" over completing the process to clear Lord Mandelson to start his new role in Washington.

Seven months after starting the position, Lord Mandelson was sacked due to his past friendship with convicted sex offender Jeffrey Epstein.

Sir Keir faced criticism for giving Lord Mandelson the role and in February, McSweeney quit his Downing Street job, saying he took "full responsibility" for advising the PM to make the appointment.

The row over Lord Mandelson's vetting has re-ignited questions among Labour MPs about Sir Keir's judgement and leadership.

Speaking to GB News, Labour MP Jonathan Brash, said: "Ultimately, we are in a situation where I don't think anyone reasonably expects the prime minister to lead the party into the next election and I think we have to refocus this government on the priorities of the British people."

Defending his actions at Prime Minister's Questions, Sir Keir said that if the Foreign Office had told him about the vetting concerns "Mandelson would not have been committed to post."

Conservative leader Kemi Badenoch said Sir Olly had been "sacked for the prime minister's own failings" and that his own MPs "know that is not fair".