This September, millions across the UK will receive a critical test message on their mobile phones as part of the government’s second nationwide emergency alert examination. First introduced in 2023, the Emergency Alert system is designed to rapidly notify the public about imminent life-threatening dangers, such as severe weather events.
When the alert is sent, all 4G and 5G mobile phones within coverage will emit a loud siren and vibrate for around ten seconds—even if set to silent. A clear message will also display on phone screens, emphasizing that this is simply a test.
Since its launch, the system has been activated during real emergencies, including Storm Darragh in December 2024, when over three million people were cautioned to stay indoors amid 90mph winds that sadly caused two fatalities.
To ensure the system remains effective and familiar to the public, officials will conduct this nationwide test at exactly 3pm on Sunday, September 7. This marks only the second large-scale trial since the system’s inception and is part of ongoing efforts to enhance national resilience.
Ahead of the test, the government will roll out a public information campaign to raise awareness, including tailored outreach for vulnerable groups such as domestic abuse victims. The campaign will also provide resources in British Sign Language.
Pat McFadden, Chancellor of the Duchy of Lancaster, highlighted the importance of the system: “Emergency Alerts have the potential to save lives by quickly delivering essential information in critical situations, including extreme storms. Like a household fire alarm, regular testing ensures it functions when we need it most.”
This alert system is a key component of the government’s wider Plan for Change, which includes a £1 billion investment in National Biosecurity Centres and a £4.2 billion program to develop advanced flood defenses to protect communities.
Since the first nationwide test in April 2023, the system has been activated five times, covering incidents such as the discovery of a World War II bomb in Plymouth and localized flash floods in Cumbria and Leicestershire. The largest deployment to date was during Storm Éowyn in January 2025, when approximately 4.5 million residents in Scotland and Northern Ireland received alerts following a red weather warning.
Béatrice Butsana-Sita, Chief Executive of the British Red Cross, emphasized the significance of preparedness: “The government’s comprehensive approach recognizes the critical role of both the voluntary sector and a ‘whole of society’ strategy. Tailored advice and support can help vulnerable people prepare, reduce crisis impact, and save lives. The real challenge lies in translating warnings into community and household readiness so everyone can respond effectively in emergencies.”
The upcoming September test underscores the UK’s commitment to improving public safety and strengthening emergency response systems nationwide.