Why Emergency Alert will go off on phones tomorrow and what to do

Millions of people will get a notification on their phones this Sunday as the government tests a new emergency alert system.

A new service that will warn people about dangerous situations, such as floods or wildfires, is being tested out nationwide. On Sunday, April 23, at 3pm, mobile phones that are compatible with 4G and 5G - and still have the alerts switched on - will emit a siren-like sound for around 10 seconds.

A message will pop up on the screen informing them that the service is being tested. You will need to acknowledge the message before you can continue using your device.

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The new system is based on similar services that are used in other countries including the US, Canada, the Netherlands and Japan. The government has said it will be a "vital tool to keep the public safe in life-threatening emergencies".

It will initially be used to warn people about severe weather situations, but the alerts could later be used for other forms of emergencies such as nuclear threats and dangerous criminals on the loose, according to the government. A spokesperson said that while the system would not be used for a “marauding terror attack” because it is difficult to give useful advice in such a situation, “there are other types of terrorist incidents where it might be relevant”.

Several tests have already been run in communities of around 20,000 people in East Suffolk and Reading, Berkshire - but the test on Sunday will be the first nationwide test.

The test alert will be sent out at 3pm. Everyone who has a 4G or 5G mobile phone, and has not opted out of reciving the alerts in their settings, will receive the