Tens of millions of mobile phones across the U.K. will blare a siren sound at the same time on Sunday (September 7, 2025) as part of government efforts to better prepare for national emergencies.
The nationwide test comes as officials seek to strengthen the country's resilience amid more frequent extreme weather events and concerns around Russia's war in Ukraine.
At 3:00 p.m. (1400 GMT), most of Britain's 87 million mobile phones and tablets will emit the noise and vibrate for about 10 seconds, the government has said.
Users will also receive a message saying the warning is only a drill, in what is just the second test of the national emergency alert system following the first in 2003.
"Just like the smoke alarm in your house, the fire alarm in this building, it's important to test these things now and again," Pat McFadden, the minister responsible for the system, told BBC radio on Thursday.
