Just like the summer exam grading fiasco, it wasn’t hard to spot the potential for the Covid testing crisis now engulfing our schools.

You could see it hurtling towards us from a very long way away - almost as far away as the hundreds of miles a government website is now expecting teachers to travel to get the swab tests they need to carry on doing their jobs.

It was always obvious that extra testing and tracing and would be crucial to the opening of schools this month. The government was told as much by its own advisers -  months ago.

And don’t forget that this was for a goal that the prime minister had said was a “national priority”.

Unfortunately, that prioritisation doesn’t appear to have translated to doing very much about it in the meantime.

Schools are already warning that pupils and teachers are having to stay home in their hundreds, just because they can’t get a test, in a situation that is becoming “increasingly out of control”.

And this is before the real cold and flu season starts, when every other pupil and teacher could end up with symptoms that lead them to require testing or isolation. This is a crisis that could rapidly deteriorate into an accidental national lockdown.

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So is help at hand? Not really, no. Health secretary Matt Hancock admitted yesterday that it could take a “matter of weeks” to resolve the problems. Another government-run ‘Lighthouse laboratory’ for analysing test swabs is the pipeline. But why is it still weeks away? Why couldn’t it have been foreseen that it would be needed right now?

Unfortunately over-promising and under delivering now seems to have become the default position for this government. We have seen it take place on everything from laptops to free school meals, and a stable set of exam results. The pattern has now become so routine that it is now exactly what we have come to expect.

So despite the obvious need for more tests as schools re-opened, the lack of them today feels utterly, grimly predictable.

What now? Yesterday Mr Hancock finally bowed to the inevitable and admitted that testing would have to be rationed. Also inevitably - and understandably - teachers and their pupils will not be top of the priority list. NHS staff and patients will come first, followed by care homes.

Where does that leave schools? These are the institutions that ministers have acknowledged are so vital for children’s education and health, not to mention their crucial role in in ensuring the economy avoids another shutdown. But ministers’ failure to act when there was still time has plunged schools into an intractable but very predictable mess.