Boris Johnson has resigned as British foreign secretary, it has been confirmed.
It's the second high-profile cabinet resignation for Theresa May in less than 24 hours, coming after the overnight resignation of Brexit secretary David Davis.
Mr Davis's junior minister Steve Baker has also resigned.
The departures follow the Friday announcement that Theresa May had gained cabinet approval to pursue a 'soft Brexit' - including a proposed EU-UK free trade area.
Mr Johnson was one of the lead voices in the 'Leave' campaign ahead of the EU referendum, and became one of the staunchest 'Brexiteers' in Mrs May's cabinet.
Jeremy Hunt, previously health secretary, will take over as foreign secretary.
The Queen has been pleased to approve the appointment of Rt Hon @Jeremy_Hunt as Secretary of State for Foreign and Commonwealth Affairs.
— UK Prime Minister (@10DowningStreet) July 9, 2018
In his resignation letter, Mr Johnson told the British prime minister: "Since I cannot in all conscience champion these proposals, I have sadly concluded that I must go.
"Brexit should be about opportunity and hope. It should be a chance to do things differently, to be more nimble and dynamic, and to maximise the particular advantages of the UK as an open, outward-looking global economy.
"The dream is dying, suffocated by needless self-doubt."
I am proud to have served as Foreign Secretary. It is with sadness that I step down: here is my letter explaining why. pic.twitter.com/NZXzUZCjdF
— Boris Johnson (@BorisJohnson) July 9, 2018
A Downing Street spokesperson said: “This afternoon, the Prime Minister accepted the resignation of Boris Johnson as Foreign Secretary.
"His replacement will be announced shortly. The Prime Minister thanks Boris for his work.”
Dominic Raab - who was also a 'Leave' supporter - has already been announced as the new Brexit secretary.