The Home Affairs Select Committee questioned Rudd last week over quotas for removal of the Windrush generation, the first large group of Caribbean migrants to arrive in the UK after World War II.
Rudd, 54, had been under increasing pressure to quit over the scandal involving Caribbean immigrants who were brought to the UK from the so-called “Windrush generation” from the 1940s.
She had faced criticism over the existence of UK Home Office deportation targets and her knowledge of them.
Rudd telephoned May to tell her of her decision, but in a letter that officially marked it she wrote: “It is with great regret that I am resigning as home secretary.
“I feel it is necessary to do so because I inadvertently misled the Home Affairs Select Committee over targets for removal of illegal immigrants during their questions on Windrush.” May said she understood why Rudd was stepping down and confirmed she had read her letter, adding: “I was very sorry to receive it.”
“The Prime Minister has accepted the resignation of the Home Secretary,” a Downing Street spokesperson said.
Rudd had been under pressure to explain apparent discrepancies between her evidence to the Parliament’s Home Affairs Select Committee last week denying any knowledge of deportation targets for illegal migrants in the UK Home Office headed by her and a memo leaked to the media that linked her to such targets.
The furore has grown since The Guardian reported that some people who came to the UK from the Caribbean in the decades after World War II had recently been refused medical care in Britain or threatened with deportation because they could not produce paperwork proving their right to reside in the country.
Those affected belong to the Windrush generation, named for the ship Empire Windrush, which in 1948 brought hundreds of Caribbean immigrants to Britain to help it rebuild after the devastation of World War II.
In recent weeks Rudd and May have apologised repeatedly to the Windrush generation, saying all pre-1973 Commonwealth immigrants who don’t already have British citizenship will get it, and those affected will get compensation.
Rudd’s resignation may further weaken May’s government.
The Prime Minister doesn’t have a majority in the UK Parliament and is struggling with Brexit negotiations.
Blame for the scandal was quickly directed toward May. Tom Watson, the deputy leader of the Labour Party, tweeted: “I see Amber Rudd is carrying the can for the person originally responsible for this scandal – Theresa May.” Shadow home secretary Diane Abbott, who had repeatedly urged Rudd to go, said she had “done the right thing”.
Abbott added that the “architect of this crisis” – Theresa May – must come before the Commons to explain “whether she knew that Amber Rudd was misleading Parliament and the public last week”.
Since May lost her parliamentary majority in elections last June, her leadership has often been under question, and she has already suffered three prior cabinet resignations.
In December, Damian Green, who was effectively May’s deputy, quit after an investigation found that he misled the public about pornography found on his parliamentary computer.
Priti Patel, the international development secretary, also resigned from the Cabinet last year after breaching ministerial rules by holding a dozen unauthorised meetings with Israeli officials during a summer vacation, and a scandal over sexual harassment in Parliament prompted the departure of May’s Defence Secretary, Michael Fallon.