First national test of Emergency Alerts system held

The first national test of the UK's Emergency Alerts system took place in April 2023, when a test message was sent to every compatible phone nationwide¹. The Cabinet Office has since described the test as the first of its kind, and the government has committed to testing the system regularly to make sure it works and to familiarise the public with the alerts².

The system sends a message to all compatible devices in a specific area using the UK's mobile network infrastructure³. During a test or a real alert, phones on 4G and 5G networks vibrate and emit a siren-like sound for up to ten seconds, even if the device is set to silent². The service does not require a phone number, does not collect data and does not track location or movements, and no app is needed³. Devices do not need mobile data or Wi-Fi to receive an alert, but phones that are switched off or on airplane mode will not receive it at the time; alerts can be rebroadcast over an extended period so that people who reconnect later still receive them³. Older feature phones on 2G networks, which the government has committed to phase out in the coming years, cannot receive Emergency Alerts³.

Since the April 2023 test, five Emergency Alerts have been sent by the government and emergency services, including during major storms when lives were at risk². During Storm Éowyn in January 2025, 4.5 million people in Scotland and Northern Ireland received an alert warning of life-threatening conditions². In Plymouth, the system helped evacuate 10,000 residents in hours after an unexploded Second World War bomb was discovered². The Resilience Action Plan records that alerts were also issued to assist with evacuations during acute flooding on the River Soar in January 2025 and on the Rivers Roe and Ive in May 2024¹.

The government published the full text of the test message ahead of the second national test, which took place on 7 September 2025². The message read:

The same message told recipients they did not need to take any action and, in a real emergency, to follow the instructions in the alert². The Lancashire Resilience Forum states that alerts are only ever issued by the UK Government or emergency services, and that anyone unsure whether an alert is genuine can check at gov.uk/alerts³. The forum also notes that the National Centre for Domestic Violence advised people with concealed devices to make sure they are turned off for the duration of the test so as not to receive the alert³.

Why it matters for households

Emergency Alerts reach compatible phones on 4G and 5G networks across the UK, including phones that are not connected to mobile data or Wi-Fi³. The alert sound is designed to be audible for hearing aid users, and depending on the phone's features the message will work with screen magnification and may be read out loud³. Alerts are one of several ways the government communicates in an emergency and do not replace updates on local news, radio, television or social media³. Households can opt out of alerts, including national tests, but the Lancashire Resilience Forum advises keeping them switched on for safety³. The government's public information campaign ahead of the September 2025 test included communications targeted at vulnerable groups such as victims of domestic abuse and the first national information video in British Sign Language².

What happens next

The second national test took place on Sunday 7 September 2025 at around 3pm, with phones vibrating and emitting a siren-like sound for up to ten seconds². The Cabinet Office said the test followed a government commitment to test the system regularly, in line with practice in other countries such as Japan and the USA². The Resilience Action Plan, published in July 2025, states that the second public national test would take place on 7 September and that, as with the first test in April 2023, the message would be sent to every compatible phone nationwide¹.

Households wanting to understand the system can read the guide to Emergency Alerts, check whether their phone will receive alerts, and find out what happens during an alert test. The guide on turning alerts off or on and the note on whether alerts track location or cost anything cover common questions, and the staying informed hub collects the related pages.