An exercise of the national emergency alert system will send a test message to mobile phones across the UK next weekend. It will mark the second test of the system, the first having taken place in 2023. On Sunday 7 September, at about 15:00, devices on 4G and 5G networks will vibrate and emit a siren for up to 10 seconds. Recipients will also receive a message making clear that the alert is a drill.

The system has previously been used to issue real warnings on five occasions, including in January during Storm Eowyn to warn people in Scotland and Northern Ireland about severe weather. During Storm Darragh in December, around 3.5 million people across Wales and the south-west of England received alerts. In February last year, a 500kg unexploded Second World War bomb found in a Plymouth garden prompted a warning to about 50,000 phones. The messages can be targeted to relatively small areas to reach those at risk. In May 2024, about 15,000 phones were alerted during floods in Cumbria, and in January this year roughly 10,000 were warned during floods in Leicestershire. The system is designed for use in the most likely emergencies and warnings would also be transmitted on television, radio and locally by knocking on doors.

Pat McFadden, Chancellor of the Duchy of Lancaster, said: “On Sunday September 7, we will hold a UK-wide test of the Emergency Alerts system to ensure it works when we need it most. It is a vital tool for keeping the nation safe when lives are on the line – and every minute matters. During Storm Darragh and Storm Eowyn, as millions faced dangerous extreme weather, I saw first-hand how effective it was at getting life-saving advice to at-risk communities in an instant. We do not use the system often, but like the fire alarm in your home, it is always on standby should we need to act.”