UK to Conduct New Emergency Alert Test on Smartphones This September

London, 8 July 2025 – Millions of mobile phones across the UK will sound a test alarm this September as part of the government’s renewed effort to strengthen national emergency alert capabilities. The test, scheduled for 7 September at 15:00 BST, will see compatible smartphones vibrate and emit a loud siren, even if the device is set to silent.

The emergency alert system, designed to warn the public of life-threatening events such as extreme weather or terror incidents, will be tested nationwide in an attempt to resolve technical flaws uncovered in previous trials. The Cabinet Office has confirmed the trial will be accompanied by a public information campaign aimed at raising awareness and preventing unnecessary panic.

A similar test in 2023 exposed serious inconsistencies. Some users received multiple messages, others none at all, particularly on the Three network, and around 7% of compatible devices failed to receive any alert. The government has said these issues have been reviewed and improvements made.

Cabinet Office Minister Pat McFadden likened the exercise to routine fire alarm tests, stating: “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.” While the minister framed the test as a safety measure, some critics remain cautious about the reach and reliability of government-led digital interventions.

Only phones using 4G or 5G networks will receive the message, excluding older handsets and those on 2G or 3G connections. Devices switched off or in airplane mode will also not receive the alert. However, phones that are not connected to mobile data or Wi-Fi will still pick up the notification, ensuring broad coverage.

Emergency alerts have already been used regionally with success. In January 2025, the system notified 4.5 million phones in Scotland and Northern Ireland during Storm Eowyn. A month earlier, 3.5 million alerts were issued in England and Wales ahead of Storm Darragh. The system was also credited with aiding the evacuation of over 10,000 residents in Plymouth after a 500kg unexploded World War Two bomb was discovered.

Despite its benefits, the system has drawn criticism from domestic abuse charities, who warned that a loud alert on a concealed phone could endanger victims. The National Centre for Domestic Violence urged vulnerable individuals to switch off such devices ahead of the test. In response, the government has published guidance on how to opt out, though officials continue to advise the public to keep alerts enabled.

A targeted public campaign, including British Sign Language content, will precede the September test to ensure all communities are informed.

With the test just two months away, ministers are hoping for a smoother rollout that restores confidence in a system designed to function in the nation’s most critical moments.

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