Millions of phones across the UK sounded with a siren on Sunday as part of a test for a new national emergency alert system. The loud alarm was planned to ring at 3pm on all devices that were using 4G and 5G networks in the UK.
The alert rang for 10 seconds and displayed a message notifying phone users that no action was needed in response to the test. Some smartphones also read out the message to recipients.
Following the test, some users reported receiving the message a minute or so early. However, others said their phone did not display the message or make a sound. Phones that were powered off or switched to airplane mode were not expected to sound.
