10 October 2026
What happens to your business phone in a power cut
The old copper line worked when the electricity didn't. Its digital replacement doesn't — and that is the part of the switch-off nobody is told about until it happens.
£9.99 a monthUp to 300 minutes a month to a UK mobile included, then 5p a minute.
An analogue landline drew its power from the exchange, down the same copper pair that carried the call. That is why the phone in the hall still worked in a power cut when nothing else in the house did. It was not a feature anyone designed for emergencies; it was a side effect of how the thing was built, and it quietly underwrote eighty years of people being able to call for help.
Its replacement does not work that way. A digital line carries your voice over your broadband connection, and your broadband needs mains electricity at your end: the router, the ONT if you are on fibre, and any switch or handset base in between. Cut the power and all of it stops. Lose the broadband on its own — a fault, a cut cable, an outage at your provider — and the phone stops with it, even though the lights are still on.
Providers are required to offer a solution to customers who depend on their landline to call emergency services, and in practice that usually means a battery backup unit for the router, or an offer of a mobile. Both are worth asking for. But a battery gives you an hour or so, not a day, and neither does anything about the far more common problem, which is the broadband being down while the power is fine.
Businesses get less help here than homes do. The emergency voice fallback being piloted on the back of the switch-off is for residential single lines; a business line is not covered. If you are a shop, a surgery, a workshop or a one-person trade, nobody is holding a safety net under your phone, and the first you will know about it is a customer telling you they tried to ring.
There is a simple test for how exposed you are. Unplug your router for ten minutes during a quiet hour and try ringing your own business number from a mobile. Whatever happens is what happens on the day it happens for real. Most people have never run it.
The way round it is not a better router, it is not having the phone depend on the building at all. Our numbers live on a carrier's network, not on a line into your premises, and when someone dials one we place an ordinary call to your mobile. There is no router in the path and no broadband in the path, so a power cut at your address does not touch it — the call simply arrives on your phone wherever you and your phone happen to be. It is £9.99 a month. Up to 300 minutes a month to a UK mobile included, then 5p a minute.
The honest version of that claim: we have moved the dependency, not removed it. Instead of needing your mains and your broadband, the call needs your mobile to have signal and charge. That is a better bet for most people most of the time — mobile masts have their own backup power, and a phone in your pocket is charged more reliably than a router is protected — but it is a different single point of failure, not the absence of one. If you are somewhere with poor mobile coverage, be honest with yourself about which risk is worse before you move.
And if nobody answers at all, the call does not vanish. It goes to voicemail, the recording and a written transcript are emailed to you, and you can ring the person back when the power comes on. Knowing who tried is not as good as answering, but it is a great deal better than a dead line and no record of who gave up.