The Glare Between Screens: 25 UK Apps and the Dark Mode Promises They Break After Sunset

At 11:04pm on a damp Tuesday in Leeds, I turned off the big light and opened twenty-five apps in a row. This is not a hobby I recommend. The room was dark, the phone was dimmed, and the cat had already claimed the good end of the sofa. Within four minutes I had been hit by more white rectangles than a provincial cinema screening of a PowerPoint presentation.

Dark mode is not one switch. It is a promise that the app will remember the lights are off — at launch, at login, on the map, inside the help centre, and in that PDF you opened because the train company wanted to prove something. Here at 124apps, we are less interested in whether an app has a dark theme in its settings menu than whether it actually holds the line when you are tired, half-awake and trying not to wake anyone else.

How we tested

Two phones, one iPhone and one Android handset, both set to system dark mode. Auto-brightness off, screen brightness at about 15%, and a living room with one small lamp doing its best. For each app we checked a cold launch, the login screen, one core task, one embedded web page or PDF, and a notification where relevant. We counted every full-white frame long enough to make you squint. We called this a flash. It is not a laboratory metric. It is, unfortunately, very easy to notice at 11pm.

The sample covered banking, travel, shopping, property, media and NHS-adjacent tools: the sort of apps that sit on a UK home screen and get opened in bed, on the last bus, or while waiting for a kettle to boil.

The worst offenders

Argos took the unwanted crown. The launch screen was white, the sign-in screen was white, and a help page inside the app behaved as if dark mode had never been invented. Seven flashes across one short session. By the end I was holding the phone at arm's length like a suspicious sandwich.

Trainline came next. The main screens were mostly fine, but the journey planner had a bright gap between screens, and the PDF ticket was a full-page white document with all the mercy of a headtorch. Six flashes. Not malicious, just careless.

A major high-street banking app — one of the big names, which we are not naming because the issue was intermittent and the app updates often — managed five. The splash screen was dark, the account view was dark, and then the login PIN pad arrived in brilliant white. It felt less like a design choice and more like a dare.

Boots and Rightmove both landed on four. Boots had a bright offers page embedded in the app; Rightmove's floor plans and some agent pages stayed stubbornly pale. The NHS App was better than expected overall, but PDF letters were still white pages. That is not a scandal. It is just the sort of small detail that matters when you are checking an appointment at midnight.

The near-misses

Tesco, Sainsbury's, Amazon, eBay and Zoopla all had moments. Sometimes it was a launch splash. Sometimes it was a web view for terms and conditions, a store locator, or a receipt. These are the apps that mostly understand the assignment but leave one door open. You notice it more because the rest of the app has been thoughtful.

Uber and Bolt were mixed. The maps were dark, which is the main thing, but the transition into some account and help screens had a pale blink. For a late-night trip home, that blink is exactly the bit you remember.

The apps that got it right

Monzo and Starling were the standouts. Dark launch screens, dark account views, no white gap between the important bits, and payment confirmations that did not feel like a camera flash. Citymapper was excellent on the map and the route steps. Spotify and BBC iPlayer behaved as though they had actually tested the app after dark. Vinted was a pleasant surprise: the browsing screens, messages and order pages all held together.

These are not luxury apps. They are everyday tools. That is what makes the difference feel so obvious. A good dark mode is not a fashion statement; it is continuity. You should be able to move from one screen to the next without your eyes resetting.

The small details that matter

The worst flashes rarely happen on the home screen. They happen in the bits app teams forget: embedded web pages for help centres, PDF tickets, council tax letters, parking receipts and delivery labels. In the UK, we have a particular talent for turning a simple task into a PDF. If an app is going to hand you a document at 11pm, it should not hand you a lightbox.

A dark mode that only covers the main dashboard is like a hotel that dims the lobby but leaves the corridor on. You notice the corridor.

What we would ask app teams to do

Test the app at 11pm with the room lights off and the brightness low. Check the splash screen, the login screen, the embedded browser, the PDF viewer and the share flow. Do not rely on the system theme if your app has its own web views. And please stop using pure white transitions as a loading state. A dark grey placeholder is not exciting, but it is kind.

The verdict

Twenty-five apps, one evening, and a lot of unnecessary squinting. The winners were Monzo, Starling, Citymapper, Spotify, BBC iPlayer and Vinted. The ones to approach with caution after dark were Argos, Trainline, Boots, Rightmove and that one high-street banking app with the glowing PIN pad.

None of this is a security crisis. It is a manners issue. At 11pm, a white flash is not a feature. It is a small, brightly lit reminder that someone tested the app in a well-lit office and then went home.