Top civil servant Olly Robbins has been sacked after his department did not inform the prime minister that Lord Mandelson had failed security vetting for the role of US ambassador.
Opposition parties are calling on the prime minister to resign but Sir Keir Starmer is insisting he wasn’t told, in an "unforgivable" omission.
He's due to speak to MPs in parliament on Monday, and address the accusations he misled them over the process of Mandelson’s appointment.
But who is Olly Robbins, the man who has lost his job over the latest Mandelson revelation and is he being used as a fall guy? And how toxic will the row be for Sir Keir?
Niall talks to hosts of fellow Sky podcast Politics at Sam and Anne’s, Anne McElvoy, executive editor at Politico and Sky’s deputy political editor, Sam Coates.
Have you got a question for Niall? Email the show: why@sky.uk