Why has Sajid Javid quit as Chancellor in a row over his closest aides? Asks Robert Peston

Why has Sajid Javid quit as Chancellor?

Because he wanted his political advisers to be his own courtiers and servants, as is the tradition, and not those of Dominic Cummings, the prime minister’s chief aide.

To the contrary, Johnson agreed with Cummings that Javid’s current special advisers should be dismissed and replaced with new advisers who would answer and report to Cummings.

The PM and Cummings believe the success of the government in these challenging times require Downing St and the Treasury to act, as far as possible, as one seamless unit.

• Sajid Javid resigns as chancellor in huge Cabinet reshuffle shock

According to one of Johnson’s close colleagues, the current prime minister admires how Cameron and Osborne acted as a two-headed single political monster when prime minister and Chancellor.

But Javid took the stripping from him of control of his aides as too great an undermining of his authority.

So Javid sacked himself, and his deputy Rishi Sunak - who Cummings and Johnson trust completely - has replaced Javid.

This was not a drive-by shooting by Cummings and Johnson, to quote the Goodwin aphorism.

But they are not naive and they always knew there was a risk he would throw himself under the Boris bus.