Boris Johnson has been rocked by another Downing Street resignation after a fifth aide quit as Cabinet ministers said they believe there is a 50/50 chance the PM will be forced out.
ANDREW PIERCE: The shock exit of Miss Mirza, head of the No10 policy unit and a highly respected figure who had worked with Boris for 14 years, was a seismic enough event in itself.
Munira Mirza was one of the PM s last remaining true believers and was by his side during his London mayoralty. But she also has close personal links to Rishi Sunak.