UK Prime Minister Keir Starmer is facing renewed political pressure after it was revealed he was not told that former US ambassador Peter Mandelson had failed security vetting before his appointment.

Mandelson later resigned over links to Jeffrey Epstein, adding to the controversy surrounding the appointment.

Starmer said it was unacceptable that he had been kept unaware while telling Parliament that proper procedures had been followed.

Critics have questioned his judgment and are calling for his resignation ahead of upcoming local elections, CNN has reported.

Starmer denied stepping down and said he would present full details to Parliament.