NHS track and trace mobile app

It would appear after a few false starts the NHS track and trace mobile app will launch soon:

Here is the link to the apps supporting website:


I’m going to wait a couple of days to see how the internet network security forums rate it, and if it’s going to (maybe) drain my battery before I install it

This is the official data privacy page

Downloaded it, seems to work OK. Can’t say much from the security angle but as for battery, I have a Google Pixel 2 so I don’t have a great battery life anyway.


They claim a 5% impact on battery life, I already have a smartwatch so I already draining power via bluetooth.

I’m interested as well to see if anyone reports data issues.

My Pixel 4 has a worse battery life than my old Pixel 2. So I have charging pads all over the place!

Wow, I always thought the 2 was the worst for battery life.

Sorry, getting a little off topic.

I’ve installed it this morning so that I can see the impact on my battery/phone. We shall see. Apparently SE23 is a ‘medium’ risk area.

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Odd. According to the Imperial College model https://imperialcollegelondon.github.io/covid19local/ Lewisham is still what I’d describe as low.

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Whereas where I live in the middle of nowhere, we are medium?

I just used the new app to check into a restaurant. Really quick and easy to use. Much better than checking in via pen and paper - and with the added sophistication of Apple’s Bluetooth contact tracking functionality.


It apparently bases it off the start of your postcode but does say that neighbouring local authorities have an impact and I think Southwark is higher.

Ah, that’s makes some sort of sense.

It’s great that this has finally been released. My company has been doing some work for the main NHS app and we saw a massive spike in onboarding (albeit from people downloading the wrong app!), but if our numbers from this morning are anything to go by, a non-trivial number of people have gone for it!

It would be cool, but perhaps not useful for a pleb like me, if the app was able to display a realtime heatmap of the whole country in terms of risk levels.


I loaded it this morning as well, although didn’t see a QR code on display when I went to Aldi in Catford this afternoon!

Does anybody know if we have to keep the app open all the time or can it be closed and as long as we keep bluetooth on it will keep checking in the blackground?

I have a feeling the contact tracing core framework is built into both iOS and Android so I think it’s logging ‘pings’ in the background - the app would translate that into useable data. It would be daft if you had to have it open all the time, even in the background.

Edit: this is pretty good:

The exposure notification system is built into Android and iOS and can only be turned on when it has an app from a government or health service installed. It’s this system that generates the codes linked to phones and interactions with other devices.

It doesn’t explicitly answer your question as far as I can see. Implicitly perhaps.

Edit2: the BBC article also suggests:

Those told to go into self-isolation because of a contact-tracing match will not be able to challenge the decision.


That’s correct, I think. In my travels today I noticed the latest version of iOS has this feature added in its changelog. Probably for the best they implement it on the OS level - I imagine you’re going to get negligble effects on battery life in this way.

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iOS already maintains a single persistent network connection to Apple’s cloud infrastructure to serve push notifications, so I imagine contact tracing will just piggyback on this, and the bandwidth used will be minimal as it’s just exchanging ids and locations.

The Bluetooth pings will definitely consume a little energy.

The BBC article suggests a battery impact of about 5%

Being that I don’t leave the house anymore and my battery doesn’t drop below 70% on any given day due to that, I’d happily pay the battery tax if it meant I could go to the cinema again!


Haha people worried about battery life rather than their own/other peoples life.

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It’s not a ridiculous concern… your phone isn’t going to be much good at tracking if it’s run out of battery!

Older phones can have terrible battery life with Bluetooth on… I wouldn’t be surprised if the reason the new app isn’t compatible with iPhones 6 or older is precisely down to battery concerns.