On Sunday the 23rd of April at 3pm UK time, there will be a nationwide test of the UK's Emergency Alert service. This system is set up to provide alerts to people when there is an immediate risk to life.
The service can send alerts on a regional or national level, and is intended to be used for things like extreme weather events. For example, if the risk of flooding was substantial in a certain area, an alert could notify users and give them the opportunity to take precautions.
While this simulation is only a test, it could still provoke anxiety in users who are unaware of the situation. With that in mind, it's worthwhile mentioning to friends and relatives in case they need assurance.
UK Emergency Alert: What devices will it appear on?
Older devices, like those that use 3G or other non-smart phones, won't receive the alert.
UK Emergency Alert: What do I need to do?
Firstly, don't panic. As mentioned, this is just a test run, so there should be nothing to worry about on that front.
When the time comes, your device may make a loud, siren-like noise and vibrate. Some devices may also read out the alert. This can happen even if your device is set to silent.
You won't need to take any action after the alert. It will appear in a similar way to a text message, with a notification. You can simply swipe the notification away, as you would with any other.
UK Emergency Alert: How can I turn it off?
Government guidance recommends that these alerts are not switched off. That's because, in a real threat-to-life scenario, they can provide crucial early warnings to help you mitigate and manage the circumstances.
If, for any reason, you do need to turn them off – for example, if you have a hidden device which you don't want found – simply search for 'Emergency Alerts' in your device settings menu. Alternatively, switching off your device, or setting it to Airplane Mode will also negate the alert.
On an iPhone, the toggles are found in the Notifications tab, and allow you to switch off 'Extreme Alerts' and 'Severe Alerts'. You'll want to turn both of these off. Android phones will work in a similar way.
UK Emergency Alert: Can they use my data?
The gov.uk website says, "data about you, your device or location will not be collected or shared." They also state that they do not need your phone number to send the alert, so that won't be held either.
The alert comes through the same cell network as your other communications, but is simply sent to all compatible devices. There is no need to use a phone number to isolate individuals.