We Got An Early Look At The UK's COVID-19 Contact-Tracing App — Here's How It Works

Prime Minister Boris Johnson and health minister Matt Hancock.

• The UK government has begun trials of its COVID-19 contact-tracing app, which is due to be rolled out country-wide through May.
• The government says the app will help it monitor and study the coronavirus outbreak and, if a large section of the population uses it, it could help ease the nation out of lockdown.
• The app uses Bluetooth signals to track how people are moving around and, if a user reports COVID-19 symptoms, it will alert those they have been in contact with over the last two weeks.
• Business Insider was able to download the app early and see how it works. Doubts over its privacy and efficacy still linger.

The UK has begun trialing its new contact-tracing app as part of its wider efforts to monitor and contain the novel coronavirus.

The trial is being rolled out on the Isle of Wight, an island off the south coast of England with roughly 141,000 people living on it, and is supposed to start rolling out to the rest of Britain through May.

Here's how it works:

When you download the app, it will generate a random ID on a daily basis, which will ping out via Bluetooth to nearby phones which also have the app installed. As you walk around, the NHS app will constantly ping out this ID and listen out for similar IDs from other phones that have the app. When your app perceives that someone else with the app is nearby, this is recorded as a "proximity event." And if an app user reports COVID-19 symptoms, the NHS will analyse that information and send out notifications to everyone they came into significant contact with.

The app has been the subject of debate from cybersecurity and privacy experts, especially since the UK has opted to build its app without using the specialized contact-tracing API from Apple and Google so that it can more easily analyse user data.

The UK's healthcare system, the NHS, has released a walkthrough of how the app works. Business Insider was also able to download the app early.

Here is what the app looks like and how it will (ostensibly) work:
This is what the app looks like on the Google Play store.



The app is available on the App Store and the Google Play store, and an NHSX spokesperson told Business Insider it intends to launch it on Huawei's App Gallery in future.

This is what the app looks like when you first open it up.




You will need to give the app permission to use battery-saving Bluetooth and to send you push notifications.




The NHS notes in a blog post about the app: "Bluetooth will only work on Android phones if Location Services are enabled, so you'll be asked to turn this feature on."

It then reiterates that the app will not collect location data.

Here's what those requests for permission look like.




Next you'll have to register your phone, which will mean putting in the first half of your postcode.




Although the app doesn't collect location data, the NHS decided to ask for the first half of users' postcodes so they can better plan resource allocation.

"The app also records your phone's make and model, which it needs to accurately measure the distance between the phones of people who've installed the app," according to the NHS.

Once the user is registered the app assigns them random ID numbers everyday, and when two users come into close contact their phones should recognise each other and log these ID numbers to create a record of which devices they have been near.

The Android version of the app will ask for your location data for Bluetooth to work, but the NHS says it won't keep this information.




The app is initially being targeted at healthcare workers, and asks them to switch Bluetooth off while they're wearing protective equipment.



There is a good reason for this. A healthcare worker wearing protective equipment and going to work is almost certainly going to come into contact with someone reporting COVID-19 symptoms by the nature of their job.

The app's Bluetooth scans will naturally pick up on this, and issue the healthcare worker with lots of alerts. But actually, they should be protected by their protective equipment, so there is no need to send these notifications.

This is the homepage, with an option to report if you are feeling unwell.




If you click on that, the app will ask you whether you have typical coronavirus symptoms.



The NHS contact-tracing app asks users about their symptoms.

You're able to back-date when you started experiencing symptoms.




If you report symptoms, users who have been in close contact with you over the past two weeks will receive a notification and be asked to self-isolate for a few days.

NCSC director Ian Levy wrote in a blogpost that this can progress in one of four ways:

• You get a clinical test and test negative. This sends out another notification saying it was a false positive.
• You get a clinical test and test positive. This sends a second notification to contacts asking them to self-isolate for 14 days and get tested.
• You don't get a test, but too few of your contacts report symptoms to statistically suggest that you were probably infectious. At this point contacts get a second notification telling them to stop self-isolating.
• You don't get a test, but enough of your contacts report symptoms to statistically suggest that you were probably infectious. This sends a notification to contacts telling them to continue self-isolating.

It looks like the NHS also asks people to double-check that the information they've entered is correct, to try and reduce trolls and false reports.



In this instance, we also had a notification that the app is only working on the Isle of Wight. Don't worry — we didn't submit our fake symptoms to the NHS.


Since the app isn't available nationwide, we can't see how its alerts work just yet. But this diagram explains what would happen next.



How the UK's contact-tracing app will work

Some questions have been raised by experts over whether using Bluetooth will effectively detect when people are near each other, especially since not using Apple and Google's API could cause complications with iPhones running the app in the background.

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