This September, millions of smartphones across the United Kingdom will ring out with a piercing siren and vibrate simultaneously as part of a nationwide test of the government’s Emergency Alert system.
Scheduled for 3:00 PM on September 7, 2025, this test aims to ensure the system is ready to warn the public of life-threatening emergencies such as severe weather, flooding, terrorist threats, or other critical incidents.
- Compatible smartphones operating on 4G and 5G networks will vibrate and emit a loud siren for approximately 10 seconds.
- The alert will appear on phone screens, including those set to silent mode, with a clear message stating it is only a test.
- Users will need to acknowledge the alert before continuing to use their devices.
- The test will reach about 90% of mobile phones in the UK, covering roughly 87 million devices.
Cabinet Office Minister Pat McFadden emphasised the importance of this test, comparing the alert system to a household fire alarm:
“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.”
Since its launch, the Emergency Alert system has been deployed in real emergencies, including:
- Storm Éowyn in January 2025, alerting 4.5 million phones in Scotland and Northern Ireland.
- Storm Darragh in December 2024, reaching 3.5 million people in Wales and the South West of England.
- The evacuation of over 10,000 residents in Plymouth during the safe removal of an unexploded Second World War bomb.
Tracey Lee, Chief Executive of Plymouth City Council, described the system as an “invaluable tool” during the bomb evacuation, highlighting its vital role in coordinating complex emergency responses.
Despite its potential, the system has faced technical issues and raised concerns:
- During the first nationwide test in April 2023, some users received alerts early or not at all, with certain networks like Three reporting significant delivery failures.
- Approximately 7% of compatible devices did not receive the alert in the previous test.
- The system does not reach phones that are turned off, in airplane mode, connected only to Wi-Fi, or using 2G or 3G networks.
- Vulnerable groups, particularly victims of domestic abuse who may have concealed phones, face risks if alerts expose their devices. The government has issued guidance on how these individuals can opt out of alerts if necessary.
The British Red Cross and other organisations have called for tailored advice to ensure people understand how to respond to alerts and how to protect themselves if needed.
A significant issue remains for individuals who do not own smartphones or use older mobile devices incompatible with the alert system. These people will not receive emergency alerts directly and must rely on traditional communication channels or assistance from others to stay informed during crises.
