Boris Johnson is to stand down as leader of the Conservative Party, following a string of high-profile ministerial resignations.
Mr Johnson has spoken to 1922 Committee chairman Sir Graham Brady and agreed to stand down, with a new Tory leader set to be in place by the party conference in October.
A No 10 spokesman said: “The Prime Minister will make a statement to the country today.”
Responding, Ms Sturgeon tweeted: “There will be a widespread sense of relief that the chaos of the last few days (indeed months) will come to an end, though notion of Boris Johnson staying on as PM until autumn seems far from ideal, and surely not sustainable?
Scottish First Minister Nicola Sturgeon
GilesG Photography/SCDI
Mr Johnson in PMQs on Wednesday
House of Commons
“Boris Johnson was always manifestly unfit to be PM and the Tories should never have elected him leader or sustained him in office for as long as they have.
“But the problems run much deeper than one individual.
“The Westminster system is broken.”
Mr Johnson clung to power in the past 48 hours despite more than 50 resignations from his government, including Education Secretary Michelle Donelan after just over a day in the job.
The Prime Minister will stay on as interim leader until the Tories elect a new leader, which is expected to be before the party’s conference in October.
The First Minister pondered whether that was “sustainable”.
Mr Johnson has spoken to 1922 Committee chairman Sir Graham Brady and agreed to stand down, with a new Tory leader set to be in place by the party conference in October.
Buckingham Palace declined to comment on whether the Queen has had any communication with Boris Johnson on Thursday morning.
The Queen is at Windsor Castle and the Court Circular recorded that she held her weekly audience by telephone with Mr Johnson on Wednesday evening.