The UK will hold a further test of its emergency alert system on 7 September this year – and putting your mobile phone on silent will not mute the alarm.
The government system is designed to warn if there is danger to life nearby, including severe weather threats. It also allows for the sending of vital information and advice.
Mobile phones will vibrate and make a siren sound for about 10 seconds, and display a message confirming that the handset takeover is just a test. There are about 87m mobile phones in the UK. People will not receive the alert if their device is turned off or connected to a 2G or 3G network. Switching a phone to silent will fail to deter the alert.
Pat McFadden, the chancellor of the duchy of Lancaster, said: “Emergency alerts have the potential to save lives, allowing us to share essential information rapidly in emergency situations including extreme storms. 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.”
The 7 September test is the system’s second nationwide drill after a test in April 2023. Some mobile phone users said at that time that their devices had not sounded off, with the problem traced to specific networks.
The system has been used five times, albeit not at a UK-wide level. Approximately 4.5 million people in Scotland and Northern Ireland received an alert during Storm Éowyn in January 2025, after the Met Office issued a severe weather warning. Other instances include a warning over an unexploded second world war bomb in Plymouth and flash flooding in Cumbria and Leicestershire.
Tracey Lee, the chief executive of Plymouth city council, said the alert “proved to be an invaluable tool during the Keyham bomb operation”. She said: “This was the first time the system had been used in a real emergency, and it played a vital role in helping us safely evacuate over 10,000 people and coordinate a complex, multi-agency response.”
Before the second nationwide test, the government will flag that it is taking place, in an effort to assist vulnerable groups such as those facing domestic abuse who may have secret mobile phones that they want to remain hidden from their partners.
Other countries including Japan and the US regularly test their emergency alert systems.
On Tuesday, McFadden will also unveil a new resilience action plan, which includes advice for how the British public should prepare for emergencies. Ministers will also publish an update on how they are implementing the 2023 biological security strategy, aimed at preparing for future pandemics.
