The test will take place at around 3pm and will see mobile phones emit a ten-second siren-like sound, accompanied by a message on screen, even if the devices are set to silent
The UK government will test its Emergency Alerts system on 7 September, sending a loud warning tone and message to millions of mobile phones across the country as part of a broader effort to strengthen national preparedness.
The test will take place at around 3pm and will see mobile phones emit a ten-second siren-like sound, accompanied by a message on screen, even if the devices are set to silent. Officials said the message will make it clear that the alert is only a test.
The trial coincides with the launch of a new Resilience Action Plan, which sets out steps to secure the country in the face of increasing risks, from extreme weather to biosecurity threats.
Pat McFadden, Chancellor of the Duchy of Lancaster, said the system could prove life-saving. “Emergency Alerts have the potential to save lives, allowing us to share essential information rapidly in emergency situations including extreme storms,” he said. “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.”
“This test is part of our action plan to build resilience across the whole country and secure the nation under the Plan for Change – from the £1bn we’re investing in a new network of National Biosecurity Centres to the £4.2bn we’re investing to build a new generation of flood defences to protect local communities,” McFadden added.
It will be the second nationwide test of the system, following the first in April 2023. Since then, five emergency alerts have been sent, including during major storms and local emergencies.
The largest activation to date came during Storm Éowyn in January 2025, when around 4.5 million people in Scotland and Northern Ireland received alerts following a red weather warning. Another 3.5 million received alerts during Storm Darragh in December 2024, which led to two fatalities across Wales and the South West of England.
Alerts have also been issued in other emergency situations, such as during localised flash flooding in Cumbria and Leicestershire, and when an unexploded World War II bomb was discovered in Plymouth.
Officials said the aim of the upcoming test is to ensure the system is working as intended and to familiarise the public with how it operates. Ahead of the test, the government will roll out a public information campaign, including targeted communications for vulnerable groups such as victims of domestic abuse. Information will also be made available in British Sign Language.
The Emergency Alerts system is designed to send vital information quickly to people in the event of danger to life nearby, using mobile networks. It mirrors systems in countries such as Japan and the United States, where regular tests are also standard practice. There are currently around 87 million mobile phones in use in the UK.
