Scottish Secretary Douglas Alexander has said Labour MPs will be feeling "despondent" following a chaotic week which has seen the sacking of Lord Mandelson and the resignation of Angela Rayner.
Sir Keir Starmer is facing questions over why he appointed Mandelson as the UK's ambassador to the US despite his known links to the convicted paedophile Jeffery Epstein.
The government said Mandelson was dismissed after emails were published which appear to show the Labour peer offering Epstein support after his conviction.
MPs and government insiders are increasingly blaming the prime minister's chief of staff Morgan McSweeney for the appointment.
Several senior Labour figures claimed that McSweeney had been resisting the inevitability of Mandelson's departure on Wednesday, with one insider describing "cold, hard fury" amongst those in Downing Street about the episode.
