Millions of UK Phones to Receive Nationwide Emergency Alert Test on Sunday

Published: 06 September 2025. The English Chronicle Desk. The English Chronicle Online.

Millions of mobile phone users across the United Kingdom are set to experience a short, but loud, alert on Sunday afternoon as the government conducts a test of its nationwide emergency alert system. Scheduled for 3pm, the ten-second alert will cause phones to vibrate and sound a siren, accompanied by an on-screen message notifying users that the alert is only a test. With around 87 million mobile devices in the UK, this exercise is aimed at ensuring that the system functions effectively in the event of life-threatening emergencies.

The government has clarified that not every phone will receive the alert. Older devices, phones not connected to 4G or 5G networks, those switched off, or in airplane mode will not participate in the test. The alert’s ten-second duration has been carefully designed to strike a balance between comprehensive testing and minimizing public inconvenience. Some disruptions are expected; for instance, the Glasgow derby between Celtic FC Women and Rangers Women’s FC has been rescheduled to 3.05pm to accommodate the test.

Pat McFadden, a senior cabinet minister, described the emergency alert system as a “national fire alarm” that requires regular testing to ensure readiness. The system is intended to warn people of imminent danger to life, including extreme weather events in specific regions. Since its initial test in April 2023, the alert system has been deployed on five occasions, with the largest usage occurring in January 2025 during Storm Éowyn, when 4.5 million people received a warning. Its first real-life application was in Plymouth in February 2024, when a 500-kilogram Second World War bomb was discovered in a residential garden and safely removed by bomb disposal experts.

The government has also issued guidance for individuals wishing to opt out of the alerts, acknowledging that those in vulnerable situations, such as victims of domestic abuse, may need to block the messages. However, setting a phone to silent mode will not prevent the alert from sounding. Tourists with non-UK mobile numbers located within the broadcast radius will also receive the test. The alert functions by broadcasting from mobile masts to every device switched on in a specific area.

Previous trials have revealed minor gaps in coverage. The first test in April 2023 failed to reach approximately 7% of devices, with network-specific issues affecting around five million phones. Officials confirmed that these problems were resolved within a week. The National Preparedness Commission, an independent body promoting strategies to strengthen the UK’s resilience to emergencies, emphasized the importance of such tests in preparing for natural disasters, national security threats, and other significant shocks. Toby Harris, chair of the NPC, highlighted the urgency of maintaining a robust emergency alert system amid volatile global conditions and increasingly extreme weather events.

This nationwide exercise underscores the UK government’s commitment to enhancing public safety and ensuring that the emergency alert system remains an effective tool for rapid communication in times of crisis.