Police in County Durham has issued a warning ahead of a new emergency alarm test.

Millions of phones across the country will sound an alarm as part of a nationwide test of a new system designed to inform people of dangerous or life-threatening situations.

The alarm will be received on 4G and 5G mobile phones, along with sound and vibration for up to 10 seconds.

Phone users then swipe or click the message before using their phone as normal.

Ahead of the test at 3pm on April 23, Durham Police's social media channel has issued a reminder.

In a statement, the police force issued a reminder of: "The UK government’s new Emergency Alerts system is now live. It will enable people to be contacted via their mobile phone when lives are in danger.

"The system is designed to help emergency services and other agencies help the public to stay safe during potentially life-threatening incidents, for example during flooding.

"It will be tested at 3pm on Sunday, April 23 when a loud, siren-like sound will be sent to all compatible mobile phones.

"A message will also appear on mobile phone screens which will only disappear once the user acknowledges it."

The system is modelled on similar schemes in the US, Canada, the Netherlands and Japan and people may receive an alert for incidents such as fires, extreme weather and severe flooding.

People who do not wish to receive the alerts will be able to opt out, but officials hope the life-saving potential of the messages means that users will keep them on. 

National Fire Chiefs Council chair Mark Hardingham said: “For 10 seconds the national test may be inconvenient for some, but please forgive us for the intrusion because, the next time you hear it, your life, and the life-saving actions of our emergency services, could depend on it.”

To find out more, visit gov.uk/alerts