Rahul Somvanshi
Your phone will blare a loud siren on September 7, 2025, at 3:00 PM as part of a nationwide emergency alert test. This 10-second warning will reach approximately 87 million mobile devices across the UK, testing a system designed to warn the public during life-threatening emergencies.
The UK government announced the second nationwide test of its Emergency Alert System will send a message in both English and Welsh to all compatible devices. When activated, phones will vibrate and emit a loud siren sound even if set to silent mode.
“Just like the fire alarm in your house, it’s important we test the system so that we know it will work if we need it,” said Pat McFadden, Chancellor of the Duchy of Lancaster, in the official announcement. “This system helps us warn people quickly when there’s danger nearby.”
The test message will reassure recipients that “you do not need to take any action” and will provide a link to gov.uk/alerts for more information.
Not all phones will receive the alert. Only devices connected to 4G or 5G networks will display the message. Phones that are turned off, in airplane mode, connected to 2G or 3G networks, or using Wi-Fi only won’t receive the notification.
This is the second public national test and the sixth activation overall since the system launched in April 2023. Previous real-world activations have warned of storms, flash floods, and even a WWII bomb discovery.
According to Cabinet Office briefings to ITV, the April 2023 test revealed technical issues, with approximately 7 percent of compatible devices failing to receive the alert—primarily on Three’s network. The carrier stated it was working with the government to resolve these problems.
For domestic abuse survivors using hidden phones, Refuge (a domestic abuse charity) recommends powering off devices during the test to prevent unwanted alerts. The government has echoed this advice in its official guidance.
People with hearing difficulties will benefit from the on-screen text display that accompanies the siren.
Consumer watchdog Which? has warned that scammers might try to exploit the test by sending fake emergency alerts. Any message asking you to take action beyond “no action needed” should be treated as suspicious.
During the 2023 test, the Society of London Theatre advised venues about the alert, and Sheffield’s Crucible Theatre briefly paused the World Snooker Championship to accommodate the test. Event organizers are advised to prepare announcements and brief attendees in advance.
This test coincides with the publication of the UK Resilience Action Plan, which outlines steps to strengthen biosecurity, flood defenses, and rapid-response frameworks.
The UK joins other nations like Japan (J-Alert system) and the United States (Wireless Emergency Alerts) that regularly conduct national emergency alert drills.
Roger Hargreaves, director of the government’s Cobra emergency committee, told MPs in July 2023 that the emergency alert system should be tested every two years to ensure the technology is working properly, as reported by The Sun and Public Technology.
The system has evolved since early cell-broadcast trials in 2019-2020 for flooding alerts.
The September 7 test will check the system’s functionality, raise awareness among mobile users, and incorporate lessons from previous activations. For more information about the Emergency Alert system, visit gov.uk/alerts.
Similar emergency alert systems have proven vital in other regions facing natural disasters, such as in California’s tsunami risk areas, where early warnings can provide crucial evacuation time.
When active, the UK system works much like the one used during the NSW bomb cyclone alert, which helped mobilize thousands of emergency service volunteers.
Recent advances in AI weather warning systems have further enhanced the precision of emergency alerts, allowing authorities to target warnings with up to 20-meter accuracy.
The Emergency Alert system has also been used for public health emergencies, similar to urgent boil water advisories that notify residents when water safety is compromised.Mass evacuation alerts, like those used during the Canadian wildfires that forced 26,000 people to evacuate, demonstrate how these systems can save lives during rapidly developing emergencies.
