The UK will carry out a further nationwide test of its Emergency Alerts system as part of continued efforts to strengthen national resilience.
On September 7 at 3pm BST, mobile phones across the UK will emit a loud siren and vibrate for around ten seconds, even if set to silent. A message will appear on screens clarifying that this is only a test.
A previous nationwide test in April 2023 exposed technical issues: some recipients received alerts earlier than planned, others did not receive them at all, and some users reported receiving duplicate messages. The government later acknowledged that about 7% of compatible devices failed to receive the alert, with users on the Three network particularly affected.
Despite those early challenges, the Emergency Alerts system has been used successfully in regional deployments across the UK on several occasions in recent years to warn the public during severe weather and other emergencies, including terrorist incidents.
Pat McFadden, Chancellor of the Duchy of Lancaster, said: “Emergency Alerts have the potential to save lives by enabling us to share essential information quickly during emergencies, including extreme storms. Like testing a fire alarm at home, it’s important we test the system so we know it will work if we need it.”
“This test is part of our action plan to build resilience across the country under the Plan for Change – from the £1 billion committed to a network of National Biosecurity Centres to the £4.2 billion investment in a new generation of flood defences to protect local communities.”
Ahead of the test, the government will run a public information campaign, with targeted communications for vulnerable groups such as victims of domestic abuse and materials available in British Sign Language.
Since its introduction, the Emergency Alerts system has proved valuable in several critical incidents. The largest deployment to date occurred during Storm Éowyn in January 2025, when about 4.5 million people in Scotland and Northern Ireland received alerts after red weather warnings were issued.
Similarly, around 3.5 million people across Wales and the South West of England received alerts during Storm Darragh in December 2024, a storm that tragically resulted in two deaths.
The system has also been used to alert residents when an unexploded World War II bomb was found in Plymouth and for localized flash flooding in Cumbria and Leicestershire.
The upcoming nationwide test coincides with wider UK government efforts to bolster national resilience. McFadden will unveil a new Resilience Action Plan outlining enhanced approaches to preparedness and emergency response.
As part of that plan, the Department for Science, Innovation and Technology (DSIT) is investing £370 million to improve the security of UK telecoms networks through research and infrastructure upgrades.
See also: Virgin Media O2 has acquired additional spectrum to boost UK mobile coverage.
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