BORIS Johnson has sensationally resigned as Foreign Secretary in a killer blow to Theresa May's government.
The MP followed Brexit secretary David Davis and stepped down leaving May's grip on power hanging in the balance. Here's what you need to know...
Why has Boris Johnson resigned?
Boris quit as Foreign Secretary on July 9 in a killer blow to May's government.
He walked out just hours after she lost Brexit Secretary David Davis as she plans to force through a soft Brexit.
The double blow - coming after Mrs May thought she'd managed to unite the Cabinet around her Brexit strategy - is the biggest threat to the PM since she took power.
A spokesman for the PM said this afternoon: "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."
Where is Boris Johnson today?
Boris was due to attend the Western Balkans Summit in East London but instead has spent the day holed up with aides deciding whether or not to follow the Brexit Secretary's lead.
Germany's Europe minister Michael Roth wrote on Twitter this afternoon: "We’re still waiting for our host... #WBLondonSummit".
He had also been due to attend a Cobra meeting about the Amesbury Novichok poisoning after Dawn Sturgess passed away in hospital but he also didn't attend that.
Boris could now be in pole position to launch a leadership bid, positioning himself as the true voice of Brexit in the face of the PM's compromises.
What is Boris Johnson's constituency?
Mr Johnson returned to Parliament in 2015 after serving as the Mayor of London for eight years.
Previously he was the MP for Henley between 2001 and 2007.
He ran as the Conservative candidate in Uxbridge and South Ruislip in the 2015 General Election.
He was a leading force in the Leave campaign in the EU referendum in 2016.
After Prime Minister David Cameron resigned, Mr Johnson did not throw his hat in the ring in the Conservative leader election.
In the 2017 General Election, Mr Johnson retained his seat in Uxbridge and South Ruislip but his majority was slashed in half.
Why has David Davis also resigned over Brexit?
David Davis resigned shortly before midnight on July 8 with a devastating letterwarning Mrs May her proposals, agreed last week at Chequers, would leave the UK in "a weak negotiating position" with Brussels.
He said there had been a "significant number of occasions in the last year or so on which I have disagreed with the Number 10 policy line".
Davis added that he had previously decided to toe the line and remain in the Cabinet "because I considered it was still possible to deliver on the mandate of the referendum, and on our manifesto commitment to leave the Customs Union and the Single Market".
MOST READ IN POLITICS
But he also delivered a damning verdict on the PM's recent approach, writing: "I am afraid that I think the current trend of policy and tactics is making that look less and less likely."
May had hoped the Cabinet agreement for a soft Brexit would help her deliver the "right Brexit" for the UK, with an offer to Brussels to share a "common rulebook" on goods and form a new UK-EU free trade area.
Boris had also fiercely attacked May's proposals and said the process was like "polishing a turd".