This Sunday 23 April UK mobile users which receive an emergency alert message to their mobile phones as part of a nationwide test.

The UK government has revealed the message that will accompany a loud alarm set to be sent to every 4G and 5G mobile phone in the country at 3 pm. The message is part of a UK-wide test of the Emergency Alerts service, which will warn citizens about life-threatening emergencies. The message will say: "This is a test of Emergency Alerts, a new UK government service that will warn you if there's a life-threatening emergency nearby. In a real emergency, follow the instructions in the alert to keep yourself and others safe. Visit gov.uk/alerts for more information. This is a test. You do not need to take any action."

While the system is intended to be used in situations such as flooding and wildfires, campaigners have raised concerns that it could reveal the location of secret phones hidden away by victims of domestic violence. However, officials have said that people can choose to opt out of the system.