Emergency alert test UK: phone alarm sounds early for some users but others don’t receive it – as it happened

Many customers on Three network report not receiving the loud alarm meant as a test for future emergencies. This blog is now closed

• UK emergency alert test: Three looking into why users failed to get text
• How to disable UK emergency alerts on your phone

Boston-based Everbridge is one of the companies providing the technology behind today's alert. Lorenzo Marchetti, the company's public affairs manager, explained the requirements of any such system:

A public alerting system should encompass three key elements- communication, synchronisation and analysis of data. For example, information might come from a weather forecast, a traffic report or through social media. Analysis of this data gives authorities a broad picture of what could occur and allows them to communicate and synchronise their actions. They can then disseminate this across specific locations or to an entire nation while ensuring that they reach the targeted people in the area. This means that effective public warning platforms can integrate several delivery methods such as radio or TVs, depending on the context of the deployment, in addition to the cell broadcast capacity.

Emergency alerts don't just benefit citizens but are also essential for giving information and directions to the emergency services, helping them understand where to go and how to direct people away from danger.

If you are concerned you could:

Avoid wearing headphones during the test