Sacked civil servant discloses he overturned vetting ruling without knowing full extent of national security concerns

• UK politics live – latest updates

The sacked senior civil servant Oliver Robbins has said he was subject to “constant pressure” when he started working at the Foreign Office to get Peter Mandelson in post as soon as possible.

He said the Cabinet Office urged the Foreign Office to allow Mandelson’s appointment as the UK’s ambassador to the US without the usual vetting process but the Foreign Office pushed back and the vetting eventually went ahead.

Sacked Foreign Office chief tells MPs he was briefed that UKSV considered Mandelson ‘a borderline case’

• UK politics live – latest updates

An account of Peter Mandelson’s vetting process given by the former top civil servant Sir Olly Robbins has raised new questions about whether Robbins was misled about the findings of the agency responsible for vetting.

Robbins, who was sacked from his role of permanent secretary at the Foreign Office last week after revelations in the Guardian, gave testimony about the process to a select committee.

PM admits he made mistake in choice of ambassador as he makes high-stakes statement to parliament over scandal

Keir Starmer has accused Olly Robbins of deliberately and repeatedly obstructing the truth about the Mandelson vetting scandal before a high-jeopardy appearance of the sacked top official before MPs on Tuesday.

Six days after the prime minister said he had learned that his pick for Washington ambassador had failed security vetting, Starmer admitted his decision to appoint him had been a fundamental mistake.