On Sunday, a national emergency alert system was tested in the UK, causing millions of phones on 4G and 5G networks to sound a loud siren at 3pm. The alert lasted for 10 seconds and

displayed a message stating that the test did not require any action from phone users. Some smartphones also read the message aloud to recipients.

Deputy Prime Minister Oliver Dowden acknowledged that the test could be annoying but argued that the system had the potential to save lives in emergency situations such as floods and wildfires.

The system is designed to warn the public of nearby life-threatening dangers, but those who do not wish to receive future alerts can opt out using their device settings. Although some users reported receiving the message early, others said that their phones did not display the message or make a sound. Photo by Océanos y dados, Wikimedia commons.