Millions of phones to receive emergency alert in UK test today

The UK Government will conduct its second nationwide Emergency Alert test today, Sunday 7 September 2025, at approximately 3pm, sending a loud siren sound and message to mobile phones across the country.

The system, designed to warn the public in the event of imminent danger to life, will affect millions of devices connected to 4G and 5G networks.

Both Android and Apple handsets will receive the alert, which forms part of the Government’s wider Resilience Action Plan to strengthen national preparedness for emergencies ranging from extreme weather to biological threats.

The timing of the test coincides with the 85th anniversary of the start of the Blitz, which began on 7 September 1940.

What will happen during the test?

At around 15:00 BST, mobile devices across the UK will:

• Emit a loud siren-like sound for roughly ten seconds

• Vibrate, even if set to silent mode

• Display a pop-up message making clear the alert is a test

This is the second nationwide trial of the system, following the first in April 2023. Since then, Emergency Alerts have been activated five times, including during Storm Éowyn in January 2025, when 4.5 million people in Scotland and Northern Ireland were warned, and during Storm Darragh in December 2024, which tragically claimed two lives.

The alerts have also been used during flash flooding in Cumbria and Leicestershire, and in Plymouth after the discovery of an unexploded WWII bomb.

Why is this test important?

The alerts allow authorities to warn people quickly about threats including flooding, fires, terrorist incidents, industrial accidents and other public safety emergencies.

Chancellor of the Duchy of Lancaster, Pat McFadden, said:

“Emergency Alerts have the potential to save lives, allowing us to share essential information rapidly in emergency situations including extreme storms. Just like the fire alarm in your house, it’s important we test the system so that we know it will work if we need it.

“This test is part of our action plan to build resilience across the whole country and secure the nation under the Plan for Change — from the £1 billion we’re investing in a new network of National Biosecurity Centres to the £4.2 billion we’re investing to build a new generation of flood defences to protect local communities.”

A wider push for resilience

The alert test forms part of the Government’s new Resilience Action Plan, which includes:

• Raising awareness of GOV.UK/PREPARE, offering practical advice on household emergency readiness

• £370m investment to strengthen UK telecoms infrastructure

• A new Memorandum of Understanding for data sharing between the National Situation Centre and devolved governments

• £1.3bn to create National Biosecurity Centres

• £15m in new funding for biosecurity capability, plus investments in biological detection technology

Later this year, the UK will also stage its largest-ever pandemic exercise, Exercise Pegasus, building on a preliminary simulation, Exercise Alkarab, held in May 2025.

Protecting vulnerable groups

The Government is also working with domestic abuse charities to help protect vulnerable groups who may be at risk if they have a concealed phone. Clear instructions on how to turn off alerts ahead of the test are available at gov.uk/alerts/opting-out.

Emergency Alert Test 2025 – FAQs

Will the alert affect landlines or Wi-Fi calls?

No. The alert will only be sent to mobile phones connected to 4G or 5G networks. Landlines, Wi-Fi calls and older 2G/3G devices will not be affected.

What if my phone doesn’t go off?

Not all devices will receive the alert. This may be due to phone settings, network coverage, or if the handset is switched off. Missing the alert today will not affect your safety in the event of a real emergency.

Can I turn off the alert?

Yes. Alerts can be disabled in the settings menu of most Android and iPhone devices. The Government has published step-by-step guidance for those who wish to opt out, particularly victims of domestic abuse with concealed phones. Guidance is available at gov.uk/alerts/opting-out.

Will the alert work if my phone is on silent or vibrate?

Yes. Phones will vibrate and play the alert sound even if set to silent.

Is there a cost for receiving the alert?

No. The Emergency Alerts service is free to use and does not require downloading an app.

Will the alert affect people visiting the UK?

Yes. Any phone roaming on a UK 4G or 5G network at the time of the alert will receive it, even if it is registered overseas.