An emergency alert has sounded across most of the country's mobile phones as the government carries out a crucial test of a life-saving system.

Millions of phones have sent out a distinctive siren-toned alarm in the second national test of the UK's alert system in as many years, which comes following a massive government publicity campaign. Officials sent out the alert at 3pm today to all 4G and 5G enabled phones, ensuring that the system is prepared for potentially deadly emergencies.

Members of the public had been warned to expect the siren from their phones following the last test in 2023, which failed to reach every eligible device.

The government had warned people for more than a week beforehand to expect the alerts before the alarming tone sounded with a message informing them a test was being carried out.

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