Your landline is going digital: the PSTN switch-off explained

What's actually happening

The UK's analogue Public Switched Telephone Network — the copper landline system that has carried our phone calls for over a century — is being retired. Every landline is moving to digital technology that carries calls over the internet, branded variously as Voice over IP (VoIP), Digital Voice or All-IP telephony. In practice your phone plugs into your broadband router instead of the socket in the wall.

The reason is simple: the old network has reached the end of its life. GOV.UK describes the PSTN as "failing due to lack of parts and, increasingly, environmental factors such as storms or heat related faults," and Ofcom recorded a 45% rise in PSTN incidents in 2024. The kit is genuinely wearing out.

The industry originally aimed to switch everything off by the end of 2025, but that was pushed back: providers are now working to a deadline of 31 January 2027. Migration is well advanced — the number of customers still on the old analogue network fell from 5.2 million in July 2024 to 3.2 million a year later — but it isn't finished, so millions of households have this change still to come.

The big change: your phone won't work in a power cut

This is the one consequence worth understanding. An old analogue phone drew its power from the phone line itself, so it kept working in a blackout. A digital phone connects through your router, and when the power goes off, so does the router — no power, no dial tone.

Regulators have planned for this. Ofcom requires providers to offer at least one hour of power-resilience access to the emergency services, free of charge, to any customer who needs their landline to call 999 — usually via a battery backup unit. The providers who signed the industry charter have committed to going beyond that one-hour minimum.

For most households this is a non-issue, because a mobile phone covers a power cut perfectly well. It only becomes important if the landline is someone's only way to call for help.

If you rely on a telecare or careline alarm

Pendant alarms and careline devices are the real risk area, because many were designed for the analogue line and can stop working once it's switched to digital. Under the industry's commitments, no telecare user should be migrated to a digital line until the provider, the customer or the telecare company has confirmed a compatible and functioning telecare solution is in place.

Power cuts are a separate question. The free battery backup Ofcom requires is for people who rely on the landline to call 999, and it lasts at least an hour. The government’s Telecare National Action Plan is clear that there is no regulatory requirement for phone companies to keep a telecare alarm working in a power cut, because alarms don’t dial 999. Whether yours keeps going depends on the alarm itself: analogue units typically run 12 to 24 hours on an internal battery, and many digital alarms have a built-in mobile SIM. So ask the alarm provider how long it works without mains power.

The action is straightforward but important: tell both your telecoms provider (the company on your phone bill) and your telecare or alarm company that you use a personal alarm, so a compatible device can be arranged before anything changes.

What you actually need to do

For most people: nothing. Your provider is required to contact you before migrating your line, and for a standard household the switch is seamless — the phone simply plugs into the router afterwards.

It's worth doing three quick checks anyway. Keep a mobile phone charged as your power-cut backup. If anyone in the house relies on the landline to call 999 — no mobile signal at home, or no mobile at all — contact the provider on your bill and ask for the free battery backup unit Ofcom requires. If someone uses a telecare alarm, also ask the alarm provider how long it runs in a power cut, because the phone company’s backup doesn’t cover the alarm. And consider signing up to your energy and water companies' Priority Services Register, which flags you for extra help in an outage.

The people to look out for are elderly relatives and anyone landline-dependent — a two-minute phone call now saves a problem later.

Who's protecting vulnerable customers

The major providers — BT, Virgin Media O2, Sky, TalkTalk, Vodafone, KCOM and others — signed a voluntary PSTN Charter, first agreed in December 2023 and updated in January 2026. In it they commit not to carry out non-voluntary migrations until they are confident vulnerable people are protected, and to go beyond Ofcom's one-hour minimum for uninterrupted access to the emergency services in a power outage.

Ofcom separately requires every provider to publish and follow a clear policy for the fair treatment of vulnerable customers, and sought explicit assurances on how firms will support people who rely on telecare alarms. In other words, the safeguards exist — but they work best when the provider knows you're one of the people who needs them, which is why the phone call matters.