Keir Starmer would have blocked Peter Mandelson over vetting , says David Lammy

Sir Keir Starmer would have blocked the appointment of Lord Mandelson as US ambassador had he known he failed security vetting, ministers have said.

The prime minister has come under pressure after it emerged this week that Mandelson was appointed despite security concerns, with Downing Street saying red flags in the vetting process were not disclosed to them by the Foreign Office.

Technology Secretary Liz Kendall told the BBC's Sunday with Laura that the prime minister "was told [Mandelson had] been granted developed vetting status... and if he had known that UK Security Vetting hadn't cleared him, he would not have made that appointment".

Starmer is set to face MPs on Monday to face questions about the appointment.

Opposition parties have called on the prime minister to resign, accusing him of misleading Parliament over his previous statements that due process had been followed in relation to the appointment.