The Landline Lockout: Twenty UK Apps, One Corded Phone and a Lot of Dead Ends

My aunt has a phone in the hall with a curly cable and a ringer loud enough to make the dog leave the room. She also has a bank account, an energy supplier, a council tax bill and a parcel habit. What she doesn't have — and has no intention of getting — is a mobile. So when her energy account locked her out in September and asked her to confirm a code sent to a mobile number, she did what she's always done: rang me, and then rang the supplier, and then waited eleven days.

That episode is the reason for this test. Between late September and early November 2026 we signed up to, verified and then deliberately tried to recover twenty UK apps using nothing but a landline number. Where a service also accepted a VoIP line (the sort you get from a broadband provider or a small business telephony outfit), we tried that too, because quite a lot of rural households and home workers now run on one.

We scored each app on three things: could you create an account, could you complete verification, and could you get back in after a lockout. Full marks meant a real human-sounding fallback. Zero meant a dead end with no phone number to ring.

The Rules We Set Ourselves

One number, one landline, no sneaky workarounds. If an app let us use a friend's mobile we didn't count it — the whole point is whether the household itself can operate the thing. We also noted whether the app told us honestly that a landline wouldn't work, or whether it took the number, said "code sent", and left us staring at a blank screen. The second behaviour is far more common than you'd hope, and it's the one that wastes an evening.

What Actually Passed

Seven of the twenty handled a landline without drama, and four of those were genuinely good about it.

• The energy supplier that rang us back. Verification arrived as an automated voice call to the landline, reading out a six-digit code. Old technology, perfectly reliable, and it took about fifteen seconds.
• HMRC. Voice call to a landline is offered as a standard option on the personal tax account, alongside an authenticator app. Neither requires a mobile number at all.
• GOV.UK One Login. The sign-in flow leans on a mobile by default, but an authenticator app works as the second factor, which means a household with a tablet and no mobile can still get through. That's a sensible fallback done quietly.
• The council tax portal. Email address, password, done. No phone number requested at any point, which after a fortnight of SMS walls felt almost rude in its decency.
• Two of the big high-street banking apps. One accepted the landline for a recorded voice call; the other let us verify in branch and then never asked again. Slow, but honest.
• A supermarket loyalty scheme. Pushy about the app, perfectly happy with the plastic card and a landline for the account. Sometimes the fallback is just the older product, still quietly running.

The Nine That Shut the Door

Nine apps in our sample simply could not be completed without a mobile number, and three of those refused to say so until after we'd entered everything else.

The pattern was depressingly consistent. A field labelled "Mobile number" that accepted our landline, validated it as fine, promised a text, and then sent nothing — because there was never a text to send. One courier app did this twice, then locked the account for "unusual activity". Another, a food delivery service, let us build a whole account and then blocked checkout with a message about verifying a device. There was no phone number to call and no web form that didn't loop back to the app.

Worst of the lot was a ticketing app that asked for a mobile during sign-up, silently accepted the landline, and then used it as the sole recovery route. When we simulated a lost password, it sent a code into the void. Two-factor recovery with no second route isn't security. It's a locked door with the key posted through the letterbox.

The VoIP Grey Zone

Four apps accepted a VoIP number at sign-up and then behaved oddly afterwards. One delivered the SMS but flagged the login as suspicious and demanded photo ID. One refused to send anything at all but offered no explanation — the screen simply refreshed. A third worked for a fortnight and then treated every login as a new device.

This matters more than it sounds. Plenty of small businesses, farmhouses on long driveways and anyone who's ditched a copper line for full-fibre broadband now sits behind a VoIP number beginning 01, 02 or 03. Those numbers look like landlines and behave like landlines, and a lot of fraud systems have decided they're suspicious by default. If you run a business from a converted barn in Cumbria, you'll meet this more often than you'd like.

Who Actually Gets Locked Out

It isn't a niche. The 2021 census found well over a million UK households with no mobile phone at all, and the number skews old, rural and less well-off. Add in people who share one handset between two adults, people whose phone is broken and awaiting a repair, people with a second home on a weak signal, and anyone who has decided — reasonably — that they don't want another SIM in their life.

What we found is that these households aren't blocked at the front door so much as at the fire exit. Signing up is often fine. It's the recovery, the re-verification, the "confirm it's you" moment after a new device or a house move where the mobile-only assumption bites, usually at the worst possible time.

What a Sensible Fallback Looks Like

Three things, and none of them are expensive:

1. A voice call to any number. If you can text a code, you can ring it. Automated voice OTP is decades-old technology and it works on a phone from 1987.
2. An authenticator app or a printed recovery code. No phone number needed at all. Offer it as a first-class route, not a hidden setting.
3. A human on a phone line, with the power to fix it. Not a chatbot. Not a form that ends in "download the app".

The Verdict

Twenty apps, seven that worked, four in a grey zone we'd call "probably fine until it isn't", and nine that quietly assumed everyone in Britain carries a smartphone. For a country that still has a working landline network in most homes, that's a lot of unnecessary dead ends. If your app can ring a phone, ring it. The hall phone still works. It's the software that's stopped listening.