Considering Kamala Harris’s fitness to take over from Joe Biden should the need arise, a top aide to the former California senator’s 2020 campaign said: “This person should not be president of the United States.”

Harris saw heavy staff turnover, with aides describing a toxic climate riven with factionalism and mismanagement. One source who worked for the vice-president declined to go on record or even discuss matters anonymously, due to the heated atmosphere around the office.

“They refused to characterise the experience of working for Harris, apart from offering a three-word assessment. It was, they said: ‘Game of Thrones’.”