UK Prime Minister Keir Starmer's chief of staff has quit - claiming he's responsible for advising Starmer to appoint Peter Mandelson as US ambassador. 

Morgan McSweeney's position had been in doubt - after emails revealed Mandelson’s relationship with sex offender Jeffrey Epstein.

Mandelson's facing a criminal investigation - into claims he'd passed sensitive information to Epstein. 

UK correspondent Mike Pearse told Ryan Bridge the scandal has Starmer's popularity waning. 

He says a new poll reveals Starmer has the support of fewer than one in five people in the UK - with some of his own MPs saying it's a matter of time before he pays the price.