Ministers have urged Brits to remain calm when their phones buzz during the latest test of the national emergency alert system at 3pm today.

Secretary of State Pat McFadden expressed confidence that UK citizens would remain calm when their phones emit a siren-like sound for 10 seconds, accompanied by a vibration and a notification.

The COBR Unit in the Cabinet Office has strategically chosen the timing of the alert to limit disruptions, as it will be the most extensive public safety drill of its kind in the UK.

Dubbed the ‘Armageddon alarm’, it will be sent to all 4G and 5G-enabled phones and tablets. 

There are about 87million mobile phones in the UK and the Government says about 95 per cent of the population has 4G or 5G access.

The alarm is designed to deliver ‘life-saving information’ in times of crisis, such as during a wildfire or storm.

Nonetheless, some specialists caution that this test may introduce various risks, potentially impacting health, breaching privacy, and endangering those in abusive situations.

An expert on acute stress reactions mentioned that such an emergency alarm might provoke heart attacks in certain individuals due to inducing a ‘flight-or-fight response.’

Work and Pensions Secretary Pat McFadden assured that Brits would maintain composure when the 10-second siren sounds on their phones.

The emergency alert is used to warn if there is a danger to life nearby, in instances like extreme weather – although today will only be a test

Medical professionals have indicated that while the alarm could, in rare cases, precipitate a heart attack, they emphasize that such occurrences are ‘highly unlikely.’ (stock image)

This is due to research showing that emergency alarms can cause participants’ heart rates to spike from an average of 74 to 111 beats per minute or higher. 

Other campaigners fear it may expose hidden phones used to seek help by abuse victims and could have terrifying consequences for those hiding devices from controlling or violent partners. 

They have urged anyone with a hidden device to disable emergency alerts ahead of the drill. 

And there are also particular worries that the alert could ‘trigger’ people with epilepsy.

Nicola Swanborough, head of external affairs at the Epilepsy Society, warned that people with the condition could suffer ‘seizures may be triggered by loud noises, such as the siren-like sound of the test’. 

The alarm has even prompted the Globe Theatre to announce that it will pause a performance of Shakespeare’s Twelfth Night so that the alarm does not disrupt the performance.

The siren sound was previously sent out in March this year and officials have now decided to repeat the nationwide exercise – prompting concerns from charities. 

The Government insists the alert — which is also used in countries like the US and Japan — is a life-saving measure, and says it will only be deployed in extreme circumstances.

At 3pm today, millions of mobile phones will vibrate and make a siren sound for roughly ten seconds. The Globe Theatre (pictured) will pause their performance

The loud sound of the emergency alert (pictured) may activate the body’s flight-or-fight system, triggering an increase in heart rate, a spike in blood pressure, and a flood of stress hormones 

It will only be used in rare but life-threatening emergencies, such as severe flooding, fires, or terror attacks, the Government says. 

Mr McFadden, the newly appointed Secretary of State for Work and Pensions, said: ‘It’s important to remember this is only a test, just like the fire drills we all do in our schools and workplaces.

‘We’re carrying out the test to make sure the system works well when we need it most, and afterwards, we’ll work with mobile network operators to assess performance.

‘The test takes just ten seconds, but it helps us keep the country safe 24 hours a day, 365 days a year.’

In the lead up to the test, there have been announcements and signs telling the public to save the date, featuring adverts on motorways, railway and bus stations to museums, GP surgeries, concerts and theatres.

Emergency Alerts have been used in five real emergencies, most recently this January when 4.5 million people across Scotland and Northern Ireland got one after Storm Éowyn.

And in Plymouth last year, it was used to help evacuate more than 10,000 residents after an unexploded Second World War bomb was discovered. 

The alert system was used in Plymouth after an unexploded World War II bomb was uncovered and had to be removed 

However, due to the concerns raised by charities, the Government has made it possible for those concerned to opt out of the alerts.

This can be done on an iPhone by going to ‘settings’ and selecting the ‘notifications’ menu, then scroll to the bottom and turn off ‘severe alerts’ and ‘extreme alerts’.

If on an Android device, search your device settings for ’emergency alerts’ and then turn off ‘severe alerts’ and ‘extreme alerts’.

The government webpage says people should contact their device manufacturer for help if they are still getting alerts after opting out.

Also, depending on the manufacturer and software version of your phone, emergency alerts settings may be called different names.

These might include ‘wireless emergency alerts’ or ’emergency broadcasts’.

The alarm will be the first time that the Emergency Alerts System has been tested in two years, following the system’s launch in 2023. 

Phones will also display a message stating that the alarm is only a test and not a genuine threat to life. 

Data about you and your device will not be collected or shared in any way during the test, regardless of whether you receive the alert or choose to opt out.

Pictured: A step-by-step guide on how to turn off the alert on iPhone and Android devices

Since the message is sent automatically via the mobile networks, the government does not need your phone number to send the alert, nor will your number be stored for the test.

Similar systems are already used widely across a number of other countries, primarily for natural disaster preparation.

Japan has one of the world’s most sophisticated systems, which combines satellite and cell broadcast technology.

This system forms part of a wider scheme called J-ALERT that informs the public in case of earthquakes, tsunamis, volcanic activity, or missile threats.

South Korea frequently uses its national cell broadcast system to alert citizens about issues ranging from weather alerts and civil emergencies to local missing persons cases.

The US has a similar system to the UK that utilises ‘wireless emergency alerts’ to send messages that look like texts with a unique sound and vibration pattern.