Sirens and vibration alerts sounded on millions of mobile phones across the United Kingdom on Sunday afternoon as the government carried out the second national test of its emergency alert system.
Around 3 p.m. on Sunday, mobiles across the country emitted an alarm for about 10 seconds accompanied by a message that made clear the alert was a drill. Prime Minister Sir Keir Starmer said "tens of millions of phones successfully sounded" in the test and described it as "an important step in keeping people safe during national emergencies." Events including sporting fixtures and performances were briefly disrupted so organisers and audiences could comply with safety advice.
The alert paused the women's Rugby World Cup match between Ireland and New Zealand in Brighton, which resumed after a short delay, and sounded between overs during England's third one-day international against South Africa in Southampton. The match organisers had warned fans via the stadium big screen that the test would take place. Theatre-goers were advised to turn their phones off before curtain-up, and drivers were urged not to be distracted while behind the wheel.
The system appeared to penetrate into parts of the London Underground; passengers reported receiving the alert on trains approaching stations. Social media also showed the alarm sounding inside the British Library, and BBC presenters covered the test live, checking whether their own phones had received the message.
Not all users had a flawless experience. Some people reported garbled or duplicated messages, including BBC science reporter Esme Stallard, whose alert appeared distorted. A government spokesperson said the alert message "was broadcast correctly and mobile operators have confirmed that the test ran as expected." Officials said the test was intended to check reach and reliability across different networks and environments.
The national alerts system, introduced after a first test in 2023, is designed to be used only for the most serious threats to life and safety. It has been used to send real warnings on several occasions, including a January alert to parts of Scotland and Northern Ireland during Storm Eowyn and a December message that reached about 3.5 million people in Wales and south-west England during Storm Darragh. Targeted messages have been deployed for more localized incidents: around 50,000 phones were warned in February last year after a 500kg unexploded Second World War bomb was found in a Plymouth back garden; roughly 15,000 phones were alerted during flooding in Cumbria in May 2024, and about 10,000 received warnings during flooding in Leicestershire in January this year.
Government officials said the alerts are one part of a broader emergency communications strategy. Warnings can be transmitted on television and radio and, where necessary, through local outreach such as door-to-door notifications. Officials also met domestic violence charities and campaigners to discuss provisions for people who may need to opt out or be protected from receiving alerts that could place them at risk.
Emergency services and mobile operators will use the feedback from Sunday's test to refine delivery and address reported issues. The government said the system's ability to target relatively small areas allows authorities to pinpoint warnings to those at risk while minimising unnecessary alarm to the wider public.