Time and date when millions of mobile phones will go off at once | Politics | News

Millions of mobile phones will sound in unison across the United Kingdom when an emergency alert system is tested next week. The second ever national alert test will take place at around 3pm on Sunday September 7, in what the Government calls โone of the largest public safety exercises of its kindโ.
Phones will vibrate and emit a siren-like tone for ten seconds, with a test message appearing on screens to make clear the alert is only a drill. Planned for Sunday afternoon, the timing has been carefully chosen by emergency planners in COBR, to minimise disruption to work and school routines.
Pat McFadden, Chancellor of the Duchy of Lancaster, said: โNext Sunday will be one of the UKโs largest public safety exercises in history, as we ensure the Emergency Alerts system is ready to help keep the country safe.
โThe test alert will be issued by COBR, the governmentโs emergency planning team whose work usually takes place behind the scenes.
โEmergency Alerts have the power to save lives. In real life emergencies, itโs vital to rapidly share warnings and advice, which is why we keep the system on standby 24/7.โ
COBR brings together ministers, senior officials and expert planners to coordinate the national response during major incidents.
Since the Emergency Alerts system was launched in April 2023, it has been used five times to warn of life-threatening danger, including during Storm รowyn in January 2025, when 4.5 million people across Scotland and Northern Ireland received an urgent warning of extreme conditions.
The system has also proved invaluable in local emergencies. In Plymouth, more than 10,000 residents were evacuated in hours after an unexploded Second World War bomb was discovered.
Only 4G and 5G enabled phones and tablets will receive the alert next Sunday. Devices also need to be turned on and within range of a mobile phone mast.
The message will say: โThis is a test of Emergency Alerts, a UK government service that will warn you if thereโs a life-threatening emergency nearby.
โYou do not need to take any action. In a real emergency, follow the instructions in the alert to keep yourself and others safe.โ
It follows the publication of the governmentโs Resilience Action Plan, which sets out plans for a ยฃ1 billion new network of National Biosecurity Centres and ยฃ4.2 billion to strengthen flood defences.