A siren-like alert will be sent to mobile phone users across the UK next month to test a new public warning system over life-threatening events such as severe weather events, the British government announced on Sunday.

A UK-wide alerts test will take place in the early evening of Sunday, April 23, which will see people receive a test message on their mobile phones.

The government said the new Emergency Alerts will be used very rarely, only being sent where there is an immediate risk to people's lives, so people may not receive an alert for months, or even years.

While currently not covered, terror alerts could also be added to the list of potential events that would trigger a notification over time.

"We are strengthening our national resilience with a new emergency alerts system, to deal with a wide range of threats - from flooding to wildfires," said Cabinet Office minister Oliver Dowden.

"It will revolutionise our ability to warn and inform people who are in immediate danger, and help us keep people safe. As we've seen in the US and elsewhere, the buzz of a phone can save a life," he said.

The Cabinet Office said that working with mobile broadcasting technology, the Emergency Alerts system is set to transform the UK's warning and informing capability, providing a means to get urgent messages quickly to nearly 90 per cent of mobile phones in a defined area and providing clear instructions about how best to respond.

The UK-wide rollout follows successful tests in East Suffolk and Reading as part of an action plan against an "ever-evolving" range of threats.

"The alerts will only ever come from the government or emergency services, and they will issue a warning, always include the details of the area impacted, and provide instructions about how best to respond - linking to gov.uk/alerts where people can receive further information," the UK Cabinet Office said.

The service has already been used in a number of other countries, including the US, Canada, the Netherlands and Japan, where it has been widely credited with saving lives, for example, during severe weather events.

"Together with every fire and rescue service in the country, I'm looking forward to having Emergency Alerts available to help us to do our jobs and to help communities in the event of emergencies," said Mark Hardingham, Chair of the UK's National Fire Chiefs Council.

"We've seen this type of system in action elsewhere across the world and we look forward to having the facility here in the UK - by working together with fire services and partners we want this system to help us to help you be as safe as you can if a crisis does hit," he said.

Broadcasting from cell towers in the vicinity of an emergency, the alerts are described as "secure, free to receive, and one-way". They do not reveal anyone's location or collect personal data and alerts can only be sent by authorised governmental and emergency services users, the government said.

"Being able to communicate warnings in a timely and accurate manner during incidents is really important to help people take action to protect themselves, their families, and their neighbours," said Caroline Douglass, Executive Director for Flood and Coastal Erosion Risk Management at the Environment Agency.

"Emergency Alerts is a fantastic addition to our toolbox that we can use in emergency situations," she said.

Emergency Alerts will be used across England, Scotland, Wales and Northern Ireland, and their initial use will focus on the most serious severe weather-related incidents, including severe flooding in England.

The British government said it has been working closely with a range of stakeholders and partners across the UK on developing the system, including colleagues from the emergency services, transport groups and the Environment Agency.