Internet outages
What happens if the internet goes down?
Payments, phones, heating apps, news, maps and the food supply all run over networks. Here is what stops first, what keeps working, and how to keep a household running offline.
It has already happened
On 19 July 2024, a single faulty software update from the security firm CrowdStrike crashed around 8.5 million Windows computers worldwide, by Microsoft's estimate. In Britain, GP surgeries lost access to appointment systems, flights were delayed and some card payments failed. The internet itself never went down. It didn't need to: a handful of services that everything depends on did.
That is the realistic shape of an internet outage. Not the whole network vanishing, but a cloud provider, a payments network, a mobile operator or a security tool failing, by accident or by attack, and taking much of daily life with it.
What stops
- Payments. Card terminals and banking apps need a connection. Cash still works.
- Phone calls. Landlines are moving to digital, which means they run through your broadband router. If the broadband or the power is down, so is the landline, unless the router has battery back-up.
- Smart homes. App-controlled heating, smart locks and cameras can stop responding. Check what each device does offline.
- Information. News, maps, travel updates and your contacts, if they only live on a phone.
- Supply. Supermarkets order stock automatically. When those systems fail, shelves empty within days, as UK shoppers saw after the 2025 retail cyber-attacks.
What keeps working
- FM radio, including emergency broadcasts.
- Cash, if you have some at home.
- Paper: maps, documents, phone numbers, plans.
- Satellite messengers, which use their own satellites rather than the mobile network.
- Licence-free walkie-talkies for the household and the street.
How to prepare
- Keep some cash at home in small notes.
- Print the essentials: ID, insurance, prescriptions, phone numbers, a map of home.
- Download offline maps and save key documents to a device that works without a connection.
- Own a wind-up or solar radio.
- Ask your broadband provider about battery back-up for the router, especially if anyone at home relies on the landline.
- For longer outages, a satellite messenger and a solar-charged power station.
- Keep three days of food and water, as the Government advises. When systems fail, shops are the first queue.
By length of outage
| Length | What you need |
|---|---|
| Hours | Cash, a charged phone and power bank, offline maps and documents |
| Days | Plus a radio, food and water for three days, a plan for medicines |
| A week or more | Plus satellite messaging, a power station with solar, and a household plan for meeting up and checking on neighbours |