Sir Keir Starmer addressed MPs in the Commons about Peter Mandelson’s vetting for his job as US ambassador.
The prime minister said officials made a “deliberate decision” not to tell him that Mandelson had failed security vetting for the job.
Conservative Party leader Kemi Badenoch accused the PM of throwing “his staff and officials under the bus”.
The PM was questioned by MPs after it emerged that vetting officers advised against Mandelson’s appointment, but the Foreign Office overruled the recommendation.