Millions of UK mobiles activated as government tests national alert system

Phones across the country play siren and vibrate in latest test of service for use during emergencies

Millions of phones across the UK played a siren and vibrated on Sunday afternoon as the government carried out a nationwide test of its emergency alert system.

The alarm, which sounded at 3pm, lasted for 10 seconds and was accompanied by a message on screen making clear it was only a test.