Gavin Williamson has been sacked as education secretary in a cabinet reshuffle that has also seen Dominic Raab removed from the Foreign Office.
Mr Raab will now become justice secretary and deputy prime minister in the most high-profile move in a reshuffle of cabinet ministers being carried out on Wednesday by Prime Minister Boris Johnson.
Earlier, Number 10 confirmed Mr Williamson had been sacked as education secretary, while Robert Buckland and Robert Jenrick have also departed their roles as justice secretary and housing, communities and local government secretary, respectively.
In a Twitter post on Wednesday afternoon, Mr Williamson said it had "been a privilege to serve as education secretary since 2019" and that he was "particularly proud of the transformational reforms I've led in post-16 education".
He added he would "look forward to continue to support the prime minister and the government".
Mr Williamson had faced regular criticism of his handling of the education brief during the COVID-19 crisis, including over the pandemic-enforced shutting of schools and a fiasco over the awarding of A-level and GCSE grades.
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Last week, Mr Williamson was widely mocked after he admitted to confusing England footballer Marcus Rashford with rugby star Maro Itoje.
As a former Tory chief whip, Mr Williamson was widely credited with securing the vast support for Mr Johnson among Conservative MPs during the party's 2019 leadership contest.
He was previously campaign manager for Theresa May's successful leadership campaign and – with a reputation as one of Westminster's most formidable organisers – it has been suggested he could prove to be a threat to Mr Johnson on the back benches.
Mr Buckland also posted on Twitter to confirm his departure.
He said he was looking to "the next adventure" and that he was "deeply proud of everything I have achieved" after serving in government for the past seven years.
Mr Jenrick, who last year was at the centre of a row over planning approval granted to a Conservative donor, tweeted that it had been a "huge privilege" to have led the Ministry of Housing, Communities and Local Government (MHCLG).
"Thank you to everyone at the department for their hard work, dedication and friendship. I'm deeply proud of all we achieved," he added.
"I will continue to support the prime minister and the government in every way I can."
Mr Jenrick's exit means there is set to be a fourth secretary of state at the department since its rebrand as MHCLG in 2018.
The prime minister is expected to complete the reshuffle of his cabinet today, with changes to lower ministerial ranks to be finalised on Thursday.
Confirmation that Mr Johnson would hold a widely-anticipated reshuffle of his ministers came during Wednesday's session of Prime Minister's Questions.
A Number 10 source said Mr Johnson would look to “put in place a strong and united team” to help the country recover from the COVID pandemic.
They also said the prime minister was looking for his government to “redouble our efforts to deliver on the people’s priorities” and Mr Johnson would appoint ministers “with a focus on uniting and levelling up the whole country”.
At a briefing for Westminster journalists, the prime minister's official spokesman said Mr Johnson had not consulted his wife Carrie on the reshuffle.
Earlier in the day, Mr Johnson's former chief adviser Dominic Cummings had branded the imminent moving of ministers as the "Carrie Reshuffle".
Labour deputy leader Angela Rayner welcomed Mr Williamson's removal as education secretary, but added: "He should have been sacked over a year ago.
"That prat's absolute idiocy, failures and uselessness have damaged the life chances of our country's children and this government has failed young people, teachers and education staff."