People in border counties may be affected by a test of the UK's nationwide alert system later today. 

Between 3pm and 4pm, a short alarm will sound on every 4G and 5G mobile device in Britain and Northern Ireland. 

Phones will make a loud siren-like sound, vibrate and read out the alert – including phones on silent. 

The alert will continue until it is acknowledged.  

People in regions bordering Northern Ireland may also receive alerts if they roam onto a UK mobile phone network area this afternoon unless they have opted out of Emergency Alerts in their device settings. 

The Department of Environment, Climate and Communications has said that some people may get a text and audio alert on their phone but there is no reason to be alarmed and no action is needed. 

"The notification will take the form of the screenshot below, however the content of the message will differ," they said in a statement.

The UK Emergency Alerts System enables the UK Government to send an 'alert' message to all mobile phones and devices. 

It will be used in case of national emergency, such as an extreme weather event, where lives are endangered. 

Similar systems exist in the Netherlands, the United States and Canada.  

Newly appointed Deputy Prime Minister Oliver Dowden has asked people to “put up with the inconvenience for 10 seconds”.  

“It could save your life,” he said.  

The Irish Government is developing a Public Warning System (PWS), which will be operational in late 2024, subject to procurement and government approval.