It has been simultaneously an open secret, and a jealously guarded one (the date, that is, not the announcement).

This afternoon's news that Sir Simon Stevens will step down as NHS Commissioning Board chief executive gives the end date - the end of July 2021.

Sir Simon has been in post for seven years, which is a long time to do such a job. He is smart enough a man to know that you can stay too long in such roles, and it has not been a secret that he has been developing an exit strategy over the past two years.

'Taking back control'
It is unclear to what extent Secretary Of State For Health But Social Care Matt 'Alan' Hancock's moves in the White Paper to 'take back control' and bring the NHS "more Matt Hancock" has made any difference to Stevensexit.

What is unambiguously clear is that the Covid19 pandemic made it effectively impossible for him to leave.

And the performance of the NHS in many regards throughout the pandemic, most obviously in the vaccination programme, has shown a system which has delivered impressively, despite its constrained resources, underlying deficit, workforce shortages, estates problems and pre-pandemic waiting list backlog.

The unfixed stuff
Many big problems facing the NHS persist, of course.

Government spending constraints have left the NHS with what was a huge backlog pre-Covid19: it is now worryingly big.

Likewise, workforce issues are far from fixed: there have been increases in recruitment, but the need for a long-term plan is likewise more than a bit pressing.

Estates and maintenance have been the victims of capital-to-revenue transfers which have stored up huge issues.

All of these must be seen in the context of political choices about public spending.

Moreover, they must be seen in the context of what the job was when Sir Simon took it in 2014: the job was one of keeping the NHS upright in what turned out to be a decade of austerity: the lowest period of funding growth in the NHS's history.

Still upright, and then some
He achieved that. He achieved a great deal, as his farewell note to NHS staff fairly lists.

Sir Simon is not wrong to state that "Thanks to the extraordinary skill and commitment of NHS staff right across the country, the reputation of the health service has never been higher, and public support deservedly never greater".

The politician wrangler
It is almost a truism to point out that Stevens is a better politician than pretty much everyone in politics in recent years, but it is none the less true for that.

His faultless ability to marshal coherent arguments crisply in front of interviewers, select committees et al is one of the sources of his command over the political and organisational NHS. The political and organisational NHS is not all of the NHS by any means, but it is intensely important to the system's party political hygiene, and to its esteem and self-esteem.

The Munchkin coaxer
It is stunningly funny that the Treasury Munchkins never worked out that Sir Simon had their number quite as comprehensively as he did.

The corporate self-importance of 'Treasury' is gob-smacking: it is simply the banking function of Government. Stevens never had any false reverence for the plaster saints of Horseguards Parade: he had a strategy for dealing with them.

It wasn't a complicated strategy - work out the Government's most salient political weak points; assemble pincer movements to put relentless pressure on said weak points; don't negotiate blatantly in public; and write them a nice, implausible long-term plan that sets direction but never commits to any hard numbers.

But it didn't have to be a complicated strategy: it just had to be effective.

Money man
And it was. The NHS got semi-protected funding; and then a modest but important gesture towards catch-up spending. And for those who will grouse about the Stevens era (and there are a few), it's time to have a look at how other areas of the public sector have fared.

Sir Simon's departure deprives us of the eagerly anticipated 'Fifteen-Year Forward View', but we should not mind too much. His tendency to centralise control in the NHS Commissioning Board and to micro-manage were the evident down-sides of a very Stevens-centric way of working for the Commissioning Board.

A subtle subversive in charge of strategy
What of his strategic legacy: the abolition of the internal market and the initially subtle subversion of the Lansley reforms with the move to locally integrated approaches to health and care provision, to become statutory in the forthcoming Health Bill?

I have been tracing Sir Simon's approach to the internal market for some years. In 2014, I was by some way the first to note that the Five-Year Forward View was 'a subtle subversion' of the Lansley reforms.

The offshoring of policymaking
Likewise, in 2015 I was the first person to observe that the Conservative Government was offshoring health policy making to Simon Stevens.

One of the pieces from that year that has aged very well is this one, in which I pointed out that Sir Simon had de facto become the Sun King of Skipton House. Simon was in charge, all right.

Towards local integrated care?
The jury is well and truly out on the move to place and system working. It sounds and feels like the right decision in a system which is so begrudgingly funded: the internal market's relevance (particularly with fee-for-service to increase activity to cut the huge backlogs) is not nothing, but it loses much of its power when there is no more money.

Locally integrated care feels like a vision around which the NHS could come together, but co-operation is hard for a system that has been legally mandated in the other direction for the past decade. Organisational sovereignty is a big thing in the NHS.

More to the point, real co-operation and real partnerships are hard to forge and easy to break.

And the jury might remain out, if Sir Simon's successor decides (or has the decision made for them) that it's hell-for-leather to cut waiting lists, no matter what.

That is not an improbable outcome.

Culture
His cultural legacy is more mixed. The NHS is, as I have long said, in far greater need of a chief anthropologist than of any chief inspector. The regulatory culture may be changing, and moving away from a 'galaxy of regulatory Death Stars' approach, but the 'Simon's in charge' approach has probably not made the NHS hierarchy a welcoming place for more maverick types (which is interesting, as Sir Simon is a sui genesis maverick of considerable scope).

Equally, the progress on race equality issues and parity of esteem for mental health have been important progressive improvements under his tenure.

It is a little surprising to see Sir Simon accepting a life peerage, but I suppose Parliament is an agreeable enough central London club.

The news of his departure date is new, and due reflection on his era will take a little while.

Sir Simon Stevens has been the most influential figure in the English NHS in the 21st century: as NHS Commissioning Board boss, he leaves the service and the system with a far better outlook than he found it.