Emergency alert test date in London: Trial set to conflict with the capital’s annual marathon

The UK government will trial an emergency alert next month, which will appear on mobile phones and tablets across the country as well as the devices of city dwellers around the capital.

The upcoming alert trial is set to be used in future emergency situations. Examples of possible situations in which it may be used include severe flooding, fires or extreme weather.

The emergency alert test coincides with the weekend of London’s annual marathon, which sees thousands of attendees line the streets of the capital to follow along with the race.

Following the announcement of the trial alert last week, several Londoners took to social media as they noted their surprise that the test is planned to conflict with "one of the busiest days in London all year."

We break down when the emergency alert test will happen, what to expect from it as well as how you can turn it off.

When the emergency alert test will happen in London

The emergency alert is expected to sound across mobile devices throughout the UK on April 23, the same day marathon participants and spectators will flock to the capital.

While the London Marathon festivities will kick off that morning, the emergency alert test is expected to go off in the early evening.

During this time, your device will sound a loud siren and vibrate, which will last for around 10 seconds. A message will also appear on the screen, clarifying it is a test emergency alert.

The full message is set to 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 an actual emergency, follow the instructions in the alert to keep yourself and others safe. Visit gov.uk/alerts for more information. This is a test. You do not need to take any action."

Those curious about what to expect, including what the siren will sound like, can check out a mock-up example of the emergency alert on the Cabinet Office’s YouTube channel.

Can you turn the emergency alert off?

Yes. While the alert is set to appear on both mobile phones and tablets, it is possible to opt out of it via the settings on your chosen device if you so wish.

For IOS devices, you will be able to locate the Emergency Alerts through the Notifications section of settings. You will find the Emergency Alerts options located at the bottom of the page, including extreme and severe alerts. If they are turned on, the toggle to the left should appear green. To turn them off, you simply tap the toggle, which should then go grey.

For those with Android devices, you can locate emergency alerts through the Apps & Notifications section in your settings. Emergency alerts should be listed at the bottom of the page. Once selected, it will take you to a new page which you can then toggle off extreme threats and severe threats as well as amber alerts.

However, authorities have warned against turning off the alert as it could make a difference in life-threatening situations.