53 members of government resigned their positions in recent days.
Boris Johnson expected to step down today - but will remain as British Prime Minister while the Conservative Party elects a new leader.
Boris Johnson is quitting as Tory leader after ministers and MPs made clear his position was untenable.
He will remain as British prime minister until a successor is in place, expected to be by the time of the Conservative Party conference in October.
Mr Johnson will make a statement to the country later today confirming the decision.
The resignation comes after Mr Johnson lost huge support among his ministers and MPs.
More than 50 MPs have resigned from government or party roles since Tuesday night, when the mass exodus was triggered by the resignations of Rishi Sunak and Sajid Javid from the Cabinet.
Mr Johnson had previously said he would "carry on" in office, despite warnings from Cabinet colleagues that this was not sustainable.

G7 Meeting To Discuss EU Diesel Shortages
Nine Gaming Companies Under Investigation By CCPC
Taoiseach Highly Critical Of Israel In UN Address
Concerns After AI Agent Hacks Australian Gov. Website
Taoiseach And Ministers To Travel To New York For UN General Assembly
Google Fined €403M Over Handling Of Location Data
Occupied Territories Bill Comes Into Effect