Officials and the BBC say a long power cut would also disable internet and mobile services, and emergency radio is the main backup.
Tamrah News Desk | November 7, 2026
A Black Sky event, a prolonged national power cut that would also take down internet and mobile services, is shaping new UK emergency backup plans, according to BBC News. The government launched its Be Ready campaign on October 22, 2026, asking households to prepare for 72 hours without essential services, Sky News reported. The BBC said the government sees no specific threat to the grid.
What Is a Black Sky Event and Why Does It Matter?
BBC News described a Black Sky event as a lengthy loss of electricity, water, shops and communications. It pointed to Lancaster, where flooding on December 5, 2015 cut power to 61,500 people. Cash machines, traffic lights and shops stopped working. The only communication systems that kept working were copper landlines and FM radio, the BBC reported. At a recent UK resilience summit, talks focused on withstanding a Black Sky event for at least 72 hours. The BBC added that the April 2025 blackout across Spain, Portugal and south western France pushed the issue higher on the agenda.
What Happens If the Internet Goes Down in a Power Cut?
Lord Harris, chair of the National Preparedness Commission, told the BBC that power cuts also stop water supplies because pumps need electricity. He said emergency services are moving from radio to mobile phone network technology, so a mobile failure would affect their communications. The government told the BBC that the move to 4G and 5G is resilient and reliable.
Ofcom updated its network resilience guidance on June 16, 2026. Law firm Osborne Clarke reported that the update sets no fixed hours of battery backup for mobile cell sites, though about four hours is good practice for fixed network cabinets. ISPreview reported on November 6 that a one hour power and internet outage in a UK town cost local firms £48,500 in lost productivity.
How Would the BBC Emergency Radio Plan Work?
BBC News said about 100 BBC staff would run an emergency radio studio with secure lines that do not depend on the internet. It would carry prepared government messages, and the scripts are already published online. Transmission towers isolated from the internet would use diesel generators to keep FM running for three days. Teams would use satellite phones, with agreed meeting points as a last resort. The BBC said FM was chosen because it works almost everywhere in a blackout or serious cyberattack. A BBC insider said the National Energy System Operator now expects power to return within two to three days.
What Is the Government Doing About UK Emergency Backup Plans?
BBC News reported that the government is spending £70m on High Altitude Pseudo Satellites, aircraft that circle over the UK and provide at least a week of emergency mobile and internet connectivity. Rico Chandra of Enduring Atmospheric Platforms told the BBC there are limits to what satellites can offer when ground networks fail.
The Be Ready campaign is the first stage of a three year effort, Sky News reported. The UK Defense Journal said the Cabinet Office runs it and more than 500 organizations are sharing the materials. According to Sky News, the checklist includes three liters of water per person each day, a battery or wind up FM radio, a charged power bank and cash. Wes Streeting, whom Sky News described as Defense Secretary, said he wanted people to be
“alert but not alarmed”
after critics called the advice scaremongering.
Will Landlines Still Work in a Power Cut After January 2027?
BBC News reported that the copper landline network will be switched off on January 31, 2027. The Register said Openreach has ruled out another delay. Worcestershire County Council says digital phone lines have no separate power connection and stop in a power cut unless a backup is provided.
Roger Kemp, the Lancaster University engineer who reviewed the 2015 outage, told the BBC,
“If anything, we’ve gone backwards.”
The government replied that copper landlines had been a useful fallback in power cuts but were now unreliable and hard to repair. The BBC added that the future of FM radio is under government review. For more, see our UK news section and technology coverage.
Conclusion
A Black Sky event would test UK emergency backup plans from the radio mast to the household kit. Readers searching for what happens if the internet goes down, the Be Ready campaign checklist, the landline switch off in 2027, BBC emergency radio, High Altitude Pseudo Satellites or UK internet outage planning should watch for updates from the government, Ofcom and Openreach.
