British Prime Minister Boris Johnson's Chief of Staff Dan Rosenfield has resigned and his Principal Private Secretary is also standing down, his office said on Thursday.

"Dan Rosenfield offered his resignation to the Prime Minister earlier today, which has been accepted," a Downing Street spokesperson said.

"Martin Reynolds also informed the Prime Minister of his intention to stand down from his role as Principal Private Secretary and the Prime Minister has agreed to this."

(Cover: Dan Rosenfield walks outside Downing Street, in London, UK, January 19, 2022. /Reuters)