Devices will vibrate and make a siren sound for 10 seconds at 3pm, with message confirming alert is a test
Millions of mobile phones will vibrate and make a siren sound across the UK on Sunday afternoon during a test of a nationwide emergency alert system.
Handset users will also receive a message on their screens reminding them the 10-second alert, which will happen at 3pm, is a test. There are about 87m mobile phones in the UK.
The government has said not all devices will receive the alert, including older phones and those not connected to 4G or 5G networks. The alert will not work on a phone that is switched off or in airplane mode.
The 10-second duration has been designed to “balance the need for comprehensive testing with reducing inconvenience to the public”, according to the government.
