Thirty years after Britain decommissioned its national air raid siren network, the government is setting up a new system to warn citizens in the event of an emergency — only this time over mobile phones.
Ministers said the system would send alerts to 4G and 5G phones about imminent life-threatening weather events, such as extreme floods or wildfires. The “broadcast” system could also be used to warn about security threats, including terrorist attacks, as it is in other countries, such as the Netherlands.
The government said on Thursday that a UK-wide test of the Emergency Alerts system would take place at 3pm BST on April 23. A message will appear on the home screen of mobile phones and the device will emit a “loud siren-like sound, even if it is set in silent,” while vibrating for up to 10 seconds.
“Getting this system operational . . . means we have another tool in our toolkit to keep the public safe in life-threatening emergencies. It could be the sound that saves your life,” cabinet office minister Oliver Dowden said.
Phone users need only swipe away the message or click “OK” on the screen, the government said. There is no need for users to register their number.
Other than the Netherlands, mobile broadcast alerts have been used in a number of countries, including the US, Canada and Japan, where they have been credited with saving lives during severe weather events.
In the UK, alerts could be used to urge residents threatened by flooding or wildfires to evacuate. During last summer’s heatwave, when temperatures reached a record-breaking 40C, England’s fire services dealt with over 50 wildfires a day — four times the number in 2021.
“We must use every tool at our disposal to keep people safe, and we need everyone to play their part,” Mark Hardingham, chair of the National Fire Chiefs council, said. “The national test may be inconvenient for some, but please forgive us for the intrusion.”
The shriek of sirens has become the defining sound of emergencies when there is a risk to life, especially in wartime. Their sound was a constant in many parts of the UK during the second world war warning of incoming German bombing raids.
The network was maintained during the cold war and was designed to give the population a four-minute warning ahead of a nuclear attack by the Soviet Union. The system was decommissioned in 1993 following the end of the cold war.
Officials said that mobile broadcasting technology meant the new system could be limited to providing warnings to 90 per cent of mobile phones in a defined geographic area, and would contain clear instructions about how to stay safe.
The alarm will work on any phone, but the system will only be used when there is an immediate risk to life, so people may not receive an alert for months or years, they added.