Bigger emergencies
Cyber attack on power, water or the NHS: what to do
Short answerA cyber attack on a service you rely on feels the same at home as any outage: no power, no card payments, delayed appointments. Your supplies, cash and a paper list of numbers and medicines cover you whatever the cause. Scammers use these incidents, so be wary of calls and texts about them.
Last checked 28 October 2026. Based on GOV.UK Be Ready, NHS England, the National Risk Register and the FCA.
It has already happened
- NHS hospitals in south-east London, June 2024. A ransomware attack on Synnovis, a pathology company, began on 3 June 2024. By early July, King's College Hospital and Guy's and St Thomas' had postponed 4,913 outpatient appointments and 1,391 planned procedures. Urgent and emergency care stayed open throughout.
- A worldwide IT failure, July 2024. A faulty CrowdStrike update on 19 July 2024 hit many industries, including some payment services. It was not a cyber attack, but it showed how one fault can stop everyday services at once.
If power is the target
The government's planning scenario for a cyber attack on electricity says homes without a backup generator would lose power instantly and without warning, and full restoration could take up to 7 days. That is why the advice is to keep three days of supplies, and why a longer blackout is worth planning for. A blackout longer than a week.
If the NHS is affected
- If your treatment is affected, your hospital or GP will tell you by text, phone or letter. They also run a helpline during big incidents.
- Emergency care stays available. Call 999 in an emergency, and use NHS 111 for anything urgent.
- Keep a written list of your regular medicines and doses, and order repeat prescriptions at least 5 working days before you run out.
Protect yourself from scams
Fraudsters often pose as banks, hospitals or utilities during a well-known incident. Do not give details to anyone who calls or texts you about it. Call the organisation back on a number you already have. If you think you have been scammed, contact Report Fraud on 0300 123 2040.
Make your own accounts harder to attack
- Use a passkey where you can, or a strong, different password for each account.
- Turn on 2-step verification for email and banking.
- Switch on automatic updates for your phone, computer and smart devices.
- Back up your photos and important files.