The Cabinet Office said the emergency alert system could be deployed in events such as severe flooding, fires or extreme weather. It noted that similar systems saved lives in the Netherlands and Japan.
The chancellor of the duchy of Lancaster, Oliver Dowden MP, said: “We are strengthening our national resilience with a new emergency alerts system, to deal with a wide range of threats – from flooding to wild fires. 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.”
The government said there had already been successful trials of the UK system in East Suffolk and Reading. A nationwide trial is set for the early evening of 23 April.
Mobile phone users will receive an emergency alert on the home screen of their device, coupled with a vibration and a loud siren-like series of beeps.
The government said the emergency alerts would be used rarely and be sent only where there was an immediate risk to life – so people may not receive an alert for months, or even years.
The government has previously been criticised for delays in developing such a system, despite successful trials having been carried out a decade ago, with some arguing such alerts would have aided communication during the coronavirus pandemic.
The UK system works on 4G and 5G phone networks and it is estimated the alerts will reach about 90% of mobile phones in a given area, with users needing to acknowledge the alert before they can use other features on their device. The siren-like sounds are expected to occur even if the phone is on silent mode; however, alerts will not be received if a device is turned off or in flight mode.
“The system uses the cell tower your phone is connected to. When an alert is triggered, all towers in the area will broadcast the alert. To do this the government does not need to know the specific location or personal data on your device,” government advice said.
If a mobile phone user receives an emergency alert, they should stop what they are doing, when it is safe to do so, and follow the instructions on the alert.
The last time the government provided helpful warnings like this, it recommended lying down and putting a paper bag on your head during a nuclear attack.