At 3pm today, the government trialled a system that aims to warn members of the public if there is a danger to life nearby, which will affect every mobile phone and tablet in Kent.

Officials from the Cabinet Office National Situation Centre sent out the alert to every 4G and 5G device across the UK.

Announcements and signage were in place across the country’s transport network in the run-up to the test. The alert was a siren-like sound no more prominent than the loudest ringtone setting on a mobile phone, a Cabinet Office spokesman added.

Here is everything you need to know:

WHAT HAPPENED?

Millions of mobile phones and tablets across the UK emitted a loud alarm and vibrated at 3pm today in a nationwide test of the new public alert system.

The message wasreceived on 4G and 5G mobile phones, along with sound and vibration for up to 10 seconds.

The alarm sounded even if the device was set on silent.

The sound and vibration of the test alert stopped automatically. All people needed to do is swipe away the message or click ‘OK’ on their phone’s home screen and continue to use their device as normal.

WHAT DID THE MESSAGE SAY?

The test message that arrives as part of the alert read:

“This is a test of Emergency Alerts, a new UK government service that will warn you if there’s a life-threatening emergency nearby. In a real emergency, follow the instructions in the alert to keep yourself and others safe. Visit for gov.uk/alerts more information.

“This is a test. You do not need to take any action.”

DO I NEED TO DO ANYTHING?

Phone users were prompted to acknowledge the alert by swiping or clicking the message before being able to continue using their device.

WHAT IS THE PURPOSE OF THIS SYSTEM?

The system, which is modelled on similar schemes in the US, Canada, the Netherlands and Japan, is intended to be used in life-threatening situations including flooding and wildfires.

WHO SENDS THE ALERTS?

Emergency alerts will only be sent by the emergency services or government departments, agencies and public bodies that deal with emergencies.

SHOULD I TURN ON LOCATION SERVICES ON MY PHONE TO ENSURE I RECEIVE ALERTS?

The government says you will get alerts based on your current location – not where you live or work, and you do not need to turn on location services to receive alerts.

The test does not reveal anyone’s location or collect personal data.

WHAT IF ALERTS COMES THROUGH WHEN I AM DRIVING?

The government is urging people to not read or respond to an emergency alert while driving or riding.

You are advised to find somewhere safe and legal to stop before reading the message, and if there is nowhere safe and legal to stop, and nobody else is in the vehicle to read the alert, you can listen to news on live radio to find out about the emergency.

The AA says motorists may prefer to switch off their electronic devices before Sunday’s test as laws banning the use of handheld phones will still apply.

CAN I OPT OUT OF THE ALERTS?

Government officials have stressed that it is easy to opt out of the system if people need their phone to stay concealed, either by turning off the alerts or simply having the phone switched off during the test.