Millions of mobile phones are to receive an emergency alert and play a loud siren sound, as the Government tests a system designed to warn the nation of disasters, terror attacks or war. The alert will come at 3pm on Sunday September 7, when phones will vibrate, play a noise for around ten seconds and display a message.
Sirens will sound even if the volume is turned down and phones do not need to be connected to a mobile signal or WiFi. However the alert will not sound if a phone is connected to a 2G or 3G network, rather than newer 4G or 5G systems, or the model is not compatible. There are 87 million mobile phones in the UK.
It will be the second test of its kind and the Government plans to hold trials on a regular basis to ensure the public understand the alerts. They can be broadcast to specific regions, including areas set to be hit by extreme storms or floods, or across the entire country if needed.
The system has been used for real warnings times since the first test in 2023, including when 4.5 million people in Scotland and Northern Ireland received an alert during Storm Éowyn in January 2025.
Pat McFadden, 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.
“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 £1 billion we’re investing in a new network of National Biosecurity Centres to the £4.2 billion we’re investing to build a new generation of flood defences to protect local communities.”
Mr McFadden will also unveils a new “Resilience Action Plan” to improve the way the government prepares for and responds to emergencies. As part of the plan, the government will raise awareness of GOV.UK/PREPARE, which gives information on simple and effective steps people can take to be more prepared for an emergency.
The Department for Science, Innovation and Technology is investing £370 million to better secure the UK’s telecommunications networks through research and investment in new technology and infrastructure.
A Pandemic Preparedness and Response Research Framework will be published by the Department for Health and Social Care, helping to coordinate scientific research to prepare for the next pandemic.
The Defence Science and Technology Laboratory (Dstl) will invest £1m through the Defence and Security Accelerator (DASA) across projects with Kromek Group, Cambridge Consultants Ltd, University of Glasgow, Queens University Belfast and Cardiff University to develop new, novel methods to detect and attribute biological incidents.
A new network of National Biosecurity Centres, announced in the National Security Strategy and backed by over £1.3 billion of investment, will bolster the UK’s defences against biological incidents, accidents and attacks.
The announcements follow the publication of the National Security Strategy last month, which set out the largest sustained increase in national security spending since the Cold War, as the government takes more action to secure the county.
In June, DEFRA announced it was investing £4.2 billion in new flood defences to keep communities safe.
This Autumn will also see the Department for Health and Social Care and the UK Health Security Agency deliver the largest pandemic exercise in the country’s history.
For the first time, the government can reveal that preparations for pandemic exercise (‘Exercise Pegasus’) are already underway. Exercise Alkarab, an initial simulation, took place in May with more than 150 participants from across the UK, including health officials and government ministers.
