what might stop, and for how long

how long it usually lasts

Seven realistic situations, how long each usually lasts, and the things that make the most difference. Five are about a difficult day or week. The last two, a pandemic and armed conflict, last longer.

1. Most resolve within hours; a small share last 1 to 3 days

   Power outage

   Loss of mains electricity, from a storm, grid fault, or planned load shedding.

   What helps most: A torch per person and a set of spare batteries, stored somewhere you can find in the dark. A charged power bank, or a car charger, so a phone lasts through a long cut.

2. Usually under 48 hours

   Water supply disruption

   Mains water cut off or advised unsafe to drink, such as a burst main or a contamination notice.

   What helps most: Stored drinking water: 2.5 to 3 litres per person per day, the figure gov.uk now uses, with 3 days as a sensible minimum. That is roughly a 9-litre stock per person, or one and a half six-packs. Extra water for pets, and for cooking and basic washing if you have room for it.

3. Days to a couple of weeks

   Supply chain and delivery delays

   Shops or deliveries disrupted by weather, fuel shortages, industrial action, or logistics problems.

   What helps most: A modest store cupboard built gradually: 3 to 7 days of shelf-stable food per person, made of things you already eat. Buying one extra of a staple each week until you reach that level, rather than a single big shop.

4. Hours to a few days, sometimes longer for widespread flooding or storms

   Extreme weather event

   Storms, flooding, heatwaves, or heavy snow that make it hard or unsafe to leave home or reach shops.

   What helps most: Enough food, water, and medication for a few days, so you have no reason to travel in dangerous conditions. Warm layers, blankets, and a hot-water bottle for cold events; a fan, cool water, and closed curtains for heat.

5. Usually short-lived, localised, and resolves within days

   Local civil disruption

   Periods of local unrest, protest, or infrastructure strain that briefly affect movement, shops, or transport in an area.

   What helps most: The same core essentials as every other scenario: a few days of food, water, and medication. Staying informed through reliable local sources: police and council channels, local news, and official alerts, rather than rumour.

6. Months or longer, lived as waves: 1 to 2 weeks at home when someone is ill, and a few weeks of thin shelves at the start

   Pandemic

   A new illness spreading widely, as COVID-19 did from 2020, with periods at home and gaps on the shelves.

   What helps most: 2 weeks of food, built up gradually from what you already eat, so an illness at home does not mean a trip to the shops. Medicines in hand: your repeat prescriptions ordered early, plus paracetamol or ibuprofen, a thermometer, and rehydration sachets.

7. Months or longer in affected regions, lived as repeated short disruptions: alerts lasting hours, power cuts of several hours a day, intermittent water and heating

   Armed conflict

   War or sustained attacks on infrastructure in a modern, connected country.

   What helps most: A safe place in your home: an interior room or corridor away from windows, below ground if you have it. The usual rule is two walls between you and the outside. Know the nearest public shelter too, such as a basement, underground car park, or metro station. A bag by the door: documents, cash in small notes, medication, chargers, a torch, water, a change of clothes, and a paper list of contacts. Electronic copies of documents on a phone as well.

what the government says

The UK government’s own site is called Prepare. It is short and calm, and takes about ten minutes to read. We checked every link on 18 September 2026.