What is a 'critical worker' ?

With the shutdown caused by Covid-19 slowly rushing towards us like a particularly laggardly iceberg, it has been announced that special measures are being put in place to help 'critical workers' - such as creche schools for their children allowing them to still go to work.

This leads to a question: what is a 'critical worker' ?

Firstly, it probably depends from crisis to crisis: in a war situation, anything to do with the military, logistics, and wartime production would be critical.

But we are facing a health emergency, and therefore doctors, nurses, and all the frontline staff are undoubtedly critical.

In trying to work out how we as a family will cope with an extended stay in our home, I made two assumptions:
1) We will continue having power (i.e. gas, electricity).
2) Water / sewage will not be interrupted.

In my view, both of these are critical. A population left without power, water or sanitation for any length of time will soon see deaths occurring regardless of Covid-19. People need power, even in the milder weather of a UK spring. Much food will be frozen, and all that dried pasta needs cooking. And to ensure these services, people need to be working on maintaining them. If not serviced, things break. And when things break anyway, we need people to fix them.

Then there is telecoms. We are being told to work from home where possible, and it can be argued that this is not critical. However people rely on the Internet nowadays, and being able to keep in contact with family and friends far away will be a boon, and in many cases a lifesaver. Your elderly friend has run out of food? With communications, you have a hope of getting some to her. Likewise, our son's school is understandably leaning heavily on online resources to teach during this extended break. And the Internet could be a great morale raiser to people trapped in their homes.

Another example: food and logistics. Many people I know are relying on online grocery deliveries for their food. This has meant they have done little or no hoarding, and will rely on as much of their deliveries making it through as possible. This is probably a good, centralised way of restricting social contact. If this was to be a prolonged situation, you could use logistics and central distribution instead  to 'fairly' dole out essentials rather than ration cards, although that's admittedly a very rocky road.

Finally, there is what I would call the essential support staff - a good example in this crisis being the teachers who will look after the children of all the critical workers.

So, I'd create a rank of essential services for this outbreak:
1) Medical and related.
2) Essential services (gas, electric, water, sewage)
3) Logistics / deliveries
4) Telecoms
5) Assorted support (e.g. teachers, planners, decision makers)

I am almost certainly missing some. for instance, how long can society last without bins being emptied? For individual households, that might be less problematic. For many communal spaces, it might be. How about postal services (i.e. Royal Mail) ?

It will be interesting to see what the government comes up with later.

 Any thoughts?