Amber Rudd’s resignation as home secretary makes her the seventh cabinet member to leave their position in the past 10 months.
She has been replaced as home secretary by Sajid Javid.
She is the seventh cabinet member Theresa May has lost since she called last June’s snap general election, where the Conservatives lost their majority in the House of Commons.
The first to leave was Defence Secretary Michael Fallon, who resigned his post after being caught up in Westminster sleaze allegations.
He admitted his standards had “fallen below the high standards required” after he admitted putting his hand on the knee of radio presenter Julia Hartley-Brewer some years ago when he resigned on November 1.
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One week later, Priti Patel resigned as international development secretary over undisclosed and unauthorised meetings in Israel, including with prime minister Benjamin Netanyahu.
In her resignation letter, she echoed the words of Mr Fallon, saying her actions “fell below the high standards” expected.
Theresa May suffered a third cabinet loss in seven weeks when Damian Green left as First Secretary of State in December.
While serving as Mrs May’s de facto deputy, Mr Green made “misleading” statements about allegations that police found pornography on computers in his parliamentary office in 2008 which breached the ministerial code.
Northern Ireland secretary James Brokenshire left the cabinet in January after standing down on health grounds, and Mrs Rudd became the fifth cabinet member to leave amid claims she misled Parliament over targets for removing illegal migrants.
Two other cabinet members – Justine Greening and Sir Patrick McLoughlin – left after January’s cabinet reshuffle.
Sir Patrick stepped down as party chairman and Ms Greening resigned from the cabinet after reportedly refusing to move from her position as education secretary to minister for work and pensions.