Emergency alert: millions of UK mobile phones to receive test message on Sunday

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.