Emergency alerts will sound sirens on mobile phones across the UK today, Tuesday, June 22
Emergency alerts which sound on mobile phones with a loud siren-like noise are being tested today.
A trial-run of the planned emergency system, designed to alert people to imminent danger through phones and tablets, is taking place across the UK this afternoon.
The government website says testing is taking place on some mobile phone networks but does not specify which customers could be affected.
It does say, however, that if you own an Android device, there is a chance you will get a test alert and your phone or tablet could make a loud siren sound.
The Emergency Alerts service, being put together by the government, is expected to launch fully later this summer.
Alerts, which are broadcast from mobile phone masts, are designed to be activated if there is a danger to life nearby.
Phones or tablets within range will be able to pick up the warning, which may also come with written advice on how to stay safe.
Mobile phone numbers are not required by the government in order to send out alerts to the public.
When the service eventually goes live, households could receive emergency alerts about incidents such as severe flooding, a fire, a terrorist attack or public health emergencies, says the government guide online.
Alerts will be sent only by emergency services, government departments and other public bodies responsible for co-ordinating emergency responses in the country.
This afternoon's test-run is between 1pm and 2pm.
Those receiving the alert will also be sent a message which says: "This is a mobile network operator test of the Emergency Alerts service. You do not need to take any action. To find out more, search for gov.uk/alerts."
To learn more about the system's roll-out and how you may be able to opt out of receiving some messages click here.
The government has set up a webpage explaining what happens when you get an emergency alert.