At about 3pm this coming Sunday all 4G and 5G mobile phones in the UK will blare a 10-second siren blast and display a test alert.

Mobile phones connected to 4G and 5G networks will vibrate and emit a siren sound for up to 10 seconds

At around 3pm on Sunday, 7 September, all 4G and 5G mobile phones in the UK will blare a 10-second siren blast and display a test alert from the Government.

At about 3pm this coming Sunday all 4G and 5G mobile phones in the UK will blare a 10-second siren blast and display a test alert.

Millions of UK phones to sound siren in national emergency alert test, part of government resilience efforts.

Devices will vibrate and make a siren sound for 10 seconds at 3pm, with message confirming alert is a test

Secretary of State Pat McFadden said he knows Brits will 'keep their cool' when their phones make a siren-like noise for 10 seconds, vibrate and show a message.

Britons urged to ‘keep their cool’ as siren-like sound to emit from millions of devices on Sept 7 at 3pm