Boris Johnson’s Number 10 operation is in danger of spiralling out of control following the loss of four of his most senior aides.

Munira Mirza, Dan Rosenfield, Jack Doyle and Martin Reynolds all left their posts in what Downing Street claimed was part of a major Number 10 reshuffle following Partygate.

In reality, Mirza’s departure was both surprising and damaging to Johnson’s political operation in equal measure.

Chris Lomas explains how Mirza’s departure unfolded, and why it has left Downing Street in crisis mode.