The builders next door have severed my electricity main cable, I've got no power or hot water.
Cant cook as everything is electric, no phone, mobile is running low

Should I be shutting or am I allowed to stay open?
Just worried that I will be uncontactable if my battery runs out

At least it's summer you could always stay at home it's not like you need to have lights or heating on, if you are out on a picnic children have to get used to using wet wipes to wash hands rather than having warm running water.

Do you normally give the children a cooked lunch, if so have they had it yet? If not and they bring a lunch box then go to the nearest park and have a picnic, text all the parents telling them under the circumstances you are going out, that your battery is running low - to save the battery for emergency use by you (ie: child has accident at park you need to phone 999) you will be turning your phone off.

We are having mains gas works in our road at the moment - they managed to dig through the mains water pipe a few weeks ago - water was running down the street for 3 hours so it was pretty obvious that the water would be turned off to mend it at some point. I took the dogs out after finishing work and when I came up our road all the neighbours were out in the street moaning about not being told the water would be turned off, one lady was saying "I've got a chicken cooked in the oven but I haven't got any water to cook my vegetables" - I offered her hot water as I have a tank but she was convinced that she would be ill if she used hot water (as it's not fresh off the mains), even though I pointed out to her that she would be boiling it, she went out and bought bottled water!