A new Emergency Alert System has been created to warn the public if there is a nearby danger to life. A test run of this service has now been scheduled for Sunday, 23 April 2023 at 3.00 pm.
Emergency Alerts are messages sent to all compatible 4G and 5G mobile phones when there’s a danger to your life, health, or property in the area you’re located. The service doesn’t require your location or phone number and only the government and the emergency services can send the alerts. If you don’t have a mobile, you’ll still be kept informed through other channels. If you get an Emergency Alert on your phone, you’ll hear a loud, siren-like sound. A message on your screen will tell you about the emergency and how best to respond.
https://www.gov.uk/alerts/announcements