The UK is preparing for another nationwide trial of its Emergency Alert system, and millions of mobile devices will ring out with a loud siren across the country. The test is designed to make sure the system is fully reliable, so that in a genuine crisis, people can receive critical updates and instructions without delay.
This nationwide alert will be sent out at 3pm on Sunday, September 7, lasting around 10 seconds with both sound and vibration. While users can turn the feature off in their phone settings, officials suggest keeping it enabled, as the service could prove vital in dangerous or life-threatening situations.
The system has already been used in real emergencies, including during Storm Darragh in December 2024, when extreme winds created hazardous conditions. It was last tested at scale in April 2023, though some phones—particularly on the Three network—did not receive the alert. Following that, improvements were promised to ensure broader coverage this time.
Who Will Receive the Alert
The alert should reach all devices connected to 4G or 5G networks in the UK. Unlike traditional messaging, it doesn’t require anyone’s phone number or personal data—the signal is sent through nearby phone masts, meaning only devices within the UK’s network will pick it up.
However, some people may not receive the alert, even if they are in the country. Reasons include:
- Having the phone turned off or on Airplane mode
- Using an older handset or a model not compatible with alerts
- Devices connected only via Wi-Fi
- Phones limited to 2G or 3G networks
For compatibility, the system works with iPhones running iOS 14.5 or later and most Android phones on version 11 or higher. Some earlier versions of Android may also work, depending on individual settings.
Safety and Privacy Considerations
While most people are encouraged to keep the alerts switched on, domestic abuse charities have advised victims with hidden phones to disable the feature to avoid drawing unwanted attention.
Drivers are also warned not to react to the notification while on the road. If you are behind the wheel when the alarm sounds, the safest option is to pull over legally before checking the message.
The government reassures the public that the system does not track movements or store personal data. Its sole purpose is to provide rapid alerts during events such as severe weather, floods, fires, or national emergencies.
