We all know that phrase “clear as mud”.

But over the past few days, this well-worn expression has seemed more relevant, more urgent, than ever.

There’s a plethora of government guidance about how schools should open to more pupils, and some of it has been clear and helpful.

But within the guidance, there are some very important elements that have proved frustratingly opaque.

And this isn’t because hardworking civil servants haven’t been working hard enough. I think they have been impressive.

No, the lack of consistent clarity lies somewhere in the wider political realm, leaving leaders and teachers to navigate on their own far too many contradictions.

Uncharted territory 

The first issue is the subject of when and how primary schools should open their doors to Reception, Year 1 and Year 6 pupils.

We all know the notional date of “from 1 June” - contingent on the government’s five tests being met - but the certainty ends there.

The guidance envisages that every eligible child will be offered a full-time place from that date, but this is obviously not going to happen.

There’s the sheer complexity of the exercise, of implementing those reams of safety measures in such a short timescale, of not having spaces that can physically accommodate these arrangements, of staff being unavailable because they are in vulnerable categories or are self-isolating.

In reality, schools will be bringing in year groups in phases over time, according to their circumstances.

There is a hint of an acknowledgement of this in that the guidance is “non-statutory”, but it is the subtlest of subtleties.

Why dismiss rotas?

An explicit statement that the need for flexibility is understood and recognised would have provided much-needed clarity, and would have avoided the embarrassment of several local authorities declaring that they’d take this approach regardless.

Delve deeper into this section of the guidance, and we find an even thornier issue, with a line saying that schools should not plan on a rota basis, either daily or weekly.

There is no rationale for this advice, of whether it is there on public health grounds, educational grounds or a mixture of both.

Given how enormously useful rotas are in the difficult circumstances in which we find ourselves, some further explanation and guidance about how any risks might be mitigated would be very helpful.

But none has been forthcoming.

More wait and see

We think there might be something on this subject in the scientific papers that are due to be published today but, if so, why couldn’t this have been provided a fortnight ago rather than a half-term week away from D-Day?

Then there is the mystery of what the government means when it says that schools and colleges should offer some “face-to-face” contact with Year 10 and Year 12 students from 1 June.

This, we are told, won’t be a return to full timetables or pupils back full time, but “some support to supplement pupils’ remote education”.

To say it is vague is an understatement.

There is no information about the maximum number of students it is considered safe to have in a setting at any one time, no guidance over the safe management of these age groups and no models to give schools and colleges options on how this might be arranged.

So, with all these issues, we have found ourselves having to advise our members to proceed with caution.

We’ve said primary leaders should not feel that they have to see that 1 June date as anything other than one on which a partial and controlled wider opening may start to happen. In many places, it will be some time later.

And we’ve advised that secondary schools and colleges rule out any Year 10 or Year 12 students returning immediately after half term.

Our recommendation is to wait to see what the government has finally proposed, and then respond.

Why is clarity so hard to offer?

What makes all this so frustrating is that this isn’t about big questions over exactly what an effective track-and-trace system looks like, or how we respond on a local basis if the reproduction rate of the virus rises, both of which do need to be answered.

Instead, it is about nitty-gritty detail, the sort of thing that could easily be addressed just through providing some clarity.

The government has at its fingertips a vast machinery of scientific, medical and public health advice.

Schools and colleges do not have access to this expertise, and they are reliant on the government to give them clear, unambiguous guidance on these essential matters. That is surely not too much to ask.

I worry that this mess isn’t an accident, but the product of a hawkish desire by some within government to make big, bold, definitive statements about reopening Britain for business, while dismissing what they may regard as mere detail.

But, as leadership teaches us, this isn’t a binary choice between a wider vision and irksome detail.

Instead, as the leaders of schools and colleges all know, it’s by attending to the details that we build confidence in any plans, in building wider support from our staff and our communities.

Today’s scientific publication will be an important next step in this national process. But there’s a long way still to go.

Geoff Barton is general secretary of the Association of School and College Leaders. He tweets @RealGeoffBarton