Emergency alert to be sent to smartphones in UK test, 15.00 7th September 2025

The national system for sending emergency alerts to mobile phones in the UK will be tested again this September, the government has said. It will see compatible phones vibrate and make a siren sound for 10 seconds while displaying a message at 15:00 BST on 7 September, even if they are set to silent. The alerts are intended for situations in which there is an imminent danger to life, such as extreme weather events or during a terror attack.