UK Emergency Alerts: the siren on your phone, explained

What Emergency Alerts are

Emergency Alerts is a UK government system that broadcasts a warning and advice message to all compatible 4G and 5G mobile phones and tablets within a defined geographic area when there's a danger to life nearby. It works by cell broadcast, which means your device doesn't need to be connected to mobile data or wifi to receive one.

Because it's a broadcast, it won't reach every device: alerts aren't received on 2G or 3G-only phones, wifi-only tablets, devices that are switched off, or incompatible handsets. But for the great majority of modern phones, if there's a serious emergency where you are, your phone will tell you.

Your privacy is protected

A common worry is that this means the government is tracking your phone. It doesn't. The system doesn't need to know your phone number or your location, and no personal data is collected. Alerts are broadcast to all compatible phones in the target area rather than sent to individuals, so no one is identified or tracked.

Receiving an alert is also completely free — you can't be charged for it, and your phone doesn't need mobile data or credit to receive one.

What a real alert looks and sounds like

A real alert makes a loud, siren-like sound and vibrates for about 10 seconds — and it sounds even if your device is set to silent, which is deliberate. The on-screen message includes advice about what's happening and what to do, plus a phone number or a link to the GOV.UK website for more information. Alerts are sent in English, and may also be sent in Welsh in Wales.

Only the emergency services and government bodies that deal with emergencies can send them, and only for life-threatening situations such as severe flooding, wildfires and extreme storms. So if your phone blares that siren, the message is genuine and worth reading immediately.

The tests, and the real alerts so far

The first UK-wide test took place on Sunday 23 April 2023 at 3pm, sending a test message to most compatible phones across the country. The second national test followed on Sunday 7 September 2025 at 3pm — only the second nationwide test — and clearly stated it was a test with no action required.

Between those tests the system was used for real five times, including during major storms when lives were at risk (Cabinet Office, July 2025). By the government's list of past alerts, two were red wind warnings: Storm Darragh in December 2024, when approximately 3.5 million people across Wales and South West England received an alert, and Storm Éowyn in January 2025, when approximately 4.5 million people in Scotland and Northern Ireland did, the largest use at the time. Two were for severe flooding, in May 2024 and January 2025, and one asked people to keep clear while a Second World War bomb was moved through Plymouth in February 2024.

Since the second test there have been two more. On 8 January 2026 alerts went to Cornwall and the Isles of Scilly under a red wind warning. On the evening of 14 August 2026 an alert went to phones across England and Wales, with a Welsh-language version in Wales, warning of a very high risk of wildfires and asking people not to do anything that could start a fire. The government called it “the most extensive use of the UK’s Emergency Alert system in response to an active incident” (Cabinet Office, 14 August 2026). It's a system that has already earned its keep.

Turning them off — and the one important exception

You can opt out, though the government advises against it for most people because alerts carry life-saving information. On an iPhone, go to Settings > Notifications, scroll to the bottom, and turn off Severe alerts and Extreme alerts. On Android, search your settings for "emergency alerts" and turn off severe and extreme alerts.

There is one situation where turning them off is the right call. Government guidance recognises that victims of domestic abuse who keep a concealed second phone may find it appropriate to switch alerts off, because the loud siren — which sounds even on silent — could otherwise reveal a hidden phone. If that applies to you or someone you're helping, that's the recognised exception.