There are a handful of big things to watch out for following Sir Philip Rutnam’s resignation as Home Office Permanent Secretary:

1. Whether in laying out his case for constructive dismissal, evidence emerges that makes it impossible for Priti Patel to remain as home secretary.
2. Whether other permanent secretaries and senior civil servants show solidarity with Rutnam, thus making it harder for Dominic Cummings to reform how they and civil servants support the Government, and harder for him to streamline the centre of government and the Cabinet Office.
3. What the soon-to-be-published independent report into the scandal of the deportation of Windrush immigrants says about the competence of the Home Office and Rutnam’s stewardship of the Home Office (difficult to believe this will make painless reading for Rutnam).

Just to be clear, in the early days of Thatcher’s and Blair/Brown’s time in office, much of the senior civil service felt under siege, offended and bruised by new prime ministers who saw traditional Whitehall as resistant to the kind of radical change they wanted.

But the noise and tremors generated in the early days of the Johnson/Cummings administration are of a significantly greater magnitude.

That reflects the greater scale of their ambition to shake up Whitehall.

But for the avoidance of doubt, neither Johnson or Cummings would want this degree of conspicuous conflict with senior civil servants, because it frustrates rather than speeds the reforms they want.

Paradoxically if their henchpeople or putative allies are briefing against civil servants, they are helping what Johnson and Cummings would see as the forces of reaction.

But the lesson of Thatcher and Blair/Brown is that in the end, prime ministers tend to get their way and Whitehall makes an accommodation, though getting there will definitely be harder and messier this time (not least because it is without precedent for a permanent secretary like Rutnam to sue the government for constructive dismissal).