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.

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.

Millions of phones will emit a siren sound and vibrate during the drill

It marks the second test of the national emergency alert system after the first in 2023