The the UK’s emergency alert system is due to be tested at 3pm on Sunday 23 April, causing all 4G and 5G-capable mobile phones in the country to make a loud siren-like sound even if they are placed on silent.

The alerts are designed to notify the public of life-threatening emergencies, but there are cases where the test could expose hidden mobile phones and put people at risk of domestic abuse or put others in danger.

Ensuring your phone is turned fully off before 3pm on Sunday will stop it from making a sound. But you can also disable the alerts via settings on your phone for a more permanent solution. Search for “emergency alerts” within settings to quickly find the options or follow the below.

iPhone

For an iPhone, open the Settings app and navigate to:

Settings > Notifications > Emergency Alerts

Toggle off both “Extreme Alerts” and “Severe Alerts”.

Android

For an Android phone or tablet with a mobile data connection, open settings and navigate to:

Settings > Safety and emergency > Wireless emergency alerts

Toggle off “Allow alerts”.

Different versions of Android from different manufacturers may look slightly different but the menus will be roughly the same.

Some other types of 4G or 5G phones may also receive the alert. Disabling the mobile phone signal by enabling airplane mode or removing the Sim card should prevent the alert, but if in doubt turn the phone completely off or remove the battery.