All compatible mobile phones in the UK will emit the government's new Emergency Alert siren when it is tested later this month.

The new warning system will play a siren type noise from phones to give notice of life threatening emergencies.

The system is set to be tested on Sunday April 23 when all UK phones will emit the warning sound. Most phones produced after 2015 will be capable of transmitting the warning.

In addition to the noise, the alert will display a message which will read: "This is a test of Emergency Alerts, a new UK government service that will are you if there's a life-threatening emergency nearby.

"If an actual emergency, follow the instructions in the alert to keep yourself and others safe. Visit gov.uk/alerts for more information.

"This is a test. You do not need to take any further action."

The new alert system is one of several ways the government will communicate news of an emergency, in addition to through local emergency services and media.

The government advises that: "If you receive an alert, read the alert carefully and follow the instructions."