Brits will be urged to use pillowcases, bedsheets or coffee filters to make safe drinking water in the event of an extended UK blackout.
Households will also be told to eat chilled or defrosted food before tinned items, cook on camping stoves in the garden and make sure family members receive enough nutrition.
And those who aren’t able to boil water or use purification tablets will be informed they can use regular unscented, household bleach to purify it.
The public health advice was revealed in scripts published by the government which would be read out by the UK’s chief medical officers, including Professor Chris Whitty, on BBC Radio 2 and Radio 4 during a nationwide blackout.
Any long-lasting powercut would most likely wipe out mobile and internet communications so battery or solar radios are considered the most reliable method for receiving government messages in this scenario.
Although the government insists the prospect of a national power outage is ‘very unlikely’, experts believe that the public needs to be better prepared.
Every person in the country, except those with back-up generators, will lose their mains electricity supply ‘instantaneously and possibly without warning’ in a nationwide blackout, according to the guidance.
This could also result in the loss of mobile and internet communications, water, sewage removal and treatment, fuel, gas and the ability to make electronic payments.
The Department of Health states this would cause ‘significant and widespread disruption and risk to health’.
Public health messages in the event of a power outage would be limited to radio and the UK’s four chief medical officers would provide advice on water shortages, food and nutrition.
On the first day of the blackout, the chief medical officers’ message would say: ‘Please listen carefully… I am about to provide you with important information.
‘You may want to write this down so that you can refer to it later. This advice will be repeated regularly.
‘We have planned in case this extraordinary situation happened, and this advice has been created by doctors and scientists to help keep you and your family healthy.’
Brits would be advised not to waste water and only use it for drinking, washing hands and preparing food.
And everyone will be told to aim to drink two litres or eight cups of fluid a day. This could be water or other liquids but not alcohol as it can dehydrate you.
Water that is still flowing normally from cold taps is still safe to drink but a long-running power cut could affect supplies.
Bottled water, soft and fizzy drinks as well as juice from tinned fruit are safe alternatives, the guidance states.
But if these run out, households are advised to source water from rainwater collection such as water butts, lakes and reservoirs which could then be made safe to drink.
They are told to filter the collected water using a ‘coffee filter, pillowcase or bedsheet’ before boiling it or using purification tablets if possible.
And unscented bleach can be used to purify the water by adding roughly a quarter of a teaspoon to every 10 litres of water, then letting it sit for 15 minutes before storing in a cool, dark place.
‘I know all the advice I am giving you might sound strange and you may be especially worried about drinking water containing bleach,’ the chief medical officers’ message states.
‘Remember that this advice has been developed by doctors and scientists to help keep you safe and healthy, as long as you follow these instructions carefully.’
The public health advice also reminds households that they will not be able to flush their toilets in a powercut and they should collect faeces in plastic bags and safely dispose of it.
The guidance also tells people to keep food outside in a clean, dry, sealed container during winter to preserve it.
‘While the power is off, most of us will not be able to cook our food in the usual way,’ it states.
‘If you have one, you could use a camping stove or barbecue outside or, if you can do so safely, light a campfire outdoors.
‘Never use camping stoves or barbecues indoors due to the severe risk of carbon monoxide poisoning, which can be fatal.’
