Less than two weeks from now, millions of smartphones will simultaneously light up in only the second ever event of its kind in British history.

The notification which will display on everyone's screens will be an emergency alert message issued by the government.

The message will read: "This is a test of Emergency Alerts, a UK government service that will warn you if there's a life-threatening emergency nearby.

"You do not need to take any action. In a real emergency, follow the instructions in the alert to keep yourself and others safe.

"Find simple and effective advice on how to prepare for emergencies at gov.uk/prepare. Visit gov.uk/alerts for more information or to view this message in Welsh."

Mobile phones on 4G and 5G networks across the country will vibrate and emit a loud si

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