An emergency alert drill will send a test message to mobile phones across the UK next weekend.
It will mark the second test of the national emergency alert system, after the first in 2023.
When will the emergency alert be sent?
On Sunday, September 7 at around 3pm, mobile phones connected to 4G and 5G networks will vibrate and emit a siren sound for up to 10 seconds.
Mobile phone users will also receive a message making clear that the alert is a drill.
What is it used for?
The government has used the system to issue real warnings five times, including in January during Storm Eowyn to warn people in Scotland and Northern Ireland about severe weather.
Approximately 3.5 million people across Wales and south-west England received an alert during Storm Darragh last December.
A 500kg unexploded Second World War bomb found in a Plymouth back garden triggered a warning to some 50,000 phones in February last year.

Messages can be targeted to relatively small areas to pinpoint those at risk.
Some 15,000 phones were alerted during flooding in Cumbria in May 2024, and 10,000 received a warning during flooding in Leicestershire in January this year.
The system is designed for use during the most likely emergencies to affect the UK and warnings would also be transmitted on television, radio and locally by knocking on doors.
Why is there going to be an emergency alert in September?
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.”
Can I turn off emergency alerts?
Yes, you can opt out of emergency alerts by going into your phone settings.
For iPhone:
- Go to your settings and select the ‘notifications’ menu.
- Scroll to the bottom.
- Turn off ‘severe alerts’ and ‘extreme alerts’.
To turn off emergency alerts on an Android phone:
- Search your settings for ‘emergency alerts’.
- Turn off ‘severe alerts’ and ‘extreme alerts’.