In April, a siren-like alert will be sent to smartphone users across the UK to test a new government public warning system.

It allows the government and emergency services to send urgent messages warning the public of life-threatening situations like flooding or moorland wildfires.

The test is to occur in the early evening of 23 April 2023. UPDATE: This will now occur at 3pm.  

Phone users must acknowledge the alert before using other features on their devices.

A message will appear on the home screens of people’s devices during the test, with vibration and a loud warning sound that will ring for about 10 seconds, even if the phone is silent.

The Emergency Alerts system is designed to deliver critical information to the public in times of emergency, such as severe weather, terrorism, or other types of incidents. It enables the government to send alerts to all compatible mobile phones in an affected area, with information on the situation, advice on what to do, and any action people need to take to keep themselves safe.

The Emergency Alerts system uses cell broadcast technology to send messages to mobile phones in a specific geographical area. This means that only people in the affected area will receive the alert, and the messages are sent to compatible phones without needing people to sign up or download any apps.

It’s worth noting that not all phones are compatible with the Emergency Alerts system. To receive these alerts, you need a smartphone that supports Cell Broadcast technology and has the feature turned on. The government advises people to check their phone’s user guide or contact their mobile phone provider to see if their phone is compatible with the Emergency Alerts system.

Overall, the Emergency Alerts system is a vital tool in the UK government’s emergency response strategy, enabling them to quickly and effectively communicate with the public during times of crisis.

People can opt-out by searching their device settings for emergency alerts and then turning off severe and extreme ones. Officials say the alerts could be life-saving, advising against switching them off.