The short answer
BT says it has until the end of January 2027 to move every customer off the old analogue phone network, and 87% had moved by June 2026 (BT stakeholder pack). For most homes the switch costs nothing: BT says the price stays the same and over 99% of phones keep working.
The real change is power. A digital line carries no electricity, so if the router has no power, the phone is dead. Providers only have to give you one hour of backup in a power cut, and that is free only if you need it (Ofcom). Older alarms that plug into the phone socket are the devices most likely to stop working.
The UK's copper phone network, the PSTN, is being switched off and every landline is moving to a digital service. BT calls its version Digital Voice. This page sets out when it happens, which devices in your home are affected, and what each fix costs, using only figures published by the government, Ofcom, BT and EE. We have not been through a switchover ourselves; this is desk research.
Prices and specs last checked by Look Into on 28 October 2026 · next check 11 January 2027 · how we picked
When it happens
GOV.UK says most customers are expected to have switched by the end of January 2027 (GOV.UK). BT puts the same date more firmly: "We have until the end of January 2027 to move all of our customers to a digital service." Its June 2026 pack says 87% of its customers had moved, with regions ranging from 80% in London to 90% in the East Midlands.
Not everyone will be cut over on one day. GOV.UK says an interim landline service runs until a digital solution is available or until 2030, whichever comes first. If you have not heard from your provider yet, you will. BT's own warning is blunt: "Inaction will result in service disruption."
Two routes, and why it matters in a power cut
How your phone behaves after the switch depends on which route your provider puts you on.
| Your setup | What happens | Phone in a power cut |
|---|---|---|
| You have broadband | The phone plugs into the router (BT calls it the hub), and calls travel over the broadband connection | Dead unless the router has battery backup. GOV.UK: handsets and routers "need your home supply" |
| Landline only, no broadband (BT) | BT switches you at the exchange. No engineer visit, and your phone stays in the same socket | BT says phones work in a power cut "if they do today". You must now dial the area code for every call |
You do not have to take broadband to keep a landline. Which? reported in February 2025 that BT will not force landline-only customers to subscribe (Which?), and GOV.UK says nobody will lose their landline because of the change.
What stops working, device by device
GOV.UK names three kinds of home equipment that may need an upgrade, a battery or network backup, or an adaptor: alarm systems, telecare devices and fax machines. This table adds the phones themselves. Where no provider publishes a price, we say so rather than estimate one.
| Device | Works after the switch? | In a power cut | Fix, and what it costs |
|---|---|---|---|
| Corded phone | Yes. BT says over 99% of phones work on Digital Voice | No on broadband Digital Voice, unless the router has battery backup | A battery backup unit for the router. Free from BT if you have additional needs. EE lists its Battery Back Up Plus at £149.99 (out of stock when we checked on 28 October 2026) |
| Cordless phone | Yes | No, before or after the switch, because the base unit runs on mains power. GOV.UK says it is basic corded handsets that an analogue line keeps powered | Keep one corded phone or a charged mobile for power cuts |
| Phones in other rooms | Yes, with an adaptor, as the phone now plugs into the router | As above | BT offers adaptors for phones in other rooms. EE lists a Home Phone Adapter at £19.99 (28 October 2026) |
| Telecare or personal alarm that plugs into the phone socket | May not. Age UK's alarm service says most landline alarms "will likely not work on the new digital system" without an adapter | No. "If there is no power, no call will be able to go through," even if the alarm has its own battery (Age UK Personal Alarms) | BT sends an engineer free to test telecare and fits a free battery backup where required. If the alarm still fails, the engineer switches you back to analogue until you have a compatible device. Long term: a SIM-based alarm that does not use the landline |
| Burglar alarm with a phone dialler or monitoring | May not. GOV.UK lists alarm systems among the devices affected | Depends on the alarm's own battery and how it signals | Ask your alarm company. None of the providers we read publishes a price for this. Our alarm monitoring cost guide covers what monitoring costs a month |
| Fax machine | May not | No | GOV.UK says it may need an upgrade or an adaptor. No price published |
Power cuts: the one-hour rule
Ofcom requires providers to offer at least one solution that gives you at least one hour of emergency calling in a power cut, free of charge for customers at risk (Ofcom, GOV.UK). One hour is the floor, not a target. In September 2024 the telecoms minister wrote to providers asking for battery backup "lasting up to eight hours" for vulnerable customers. That was a request in a letter, not a rule, and we found no later requirement (ISPreview).
What providers offer:
- Battery backup unit. It keeps the router and the fibre box powered. BT gives one free to customers with additional needs. EE's newer unit goes into hibernation when 25% of its charge is left, so you can wake it for an emergency call (EE).
- Hybrid phone. A home phone with a built-in battery that switches to the mobile network. Which? reports "at least one hour's talk time", free for BT customers with additional needs who have 4G signal.
- Your own mobile. GOV.UK recommends a mobile as backup and notes that 999 calls can use any mobile network.
If you are not eligible for a free unit, a mini UPS for the router costs from about £7.50 per hour of backup in our router battery backup guide. The cheapest option is a charged mobile phone and a power bank to keep it going. A portable power station can run the router itself. Our Always-On Load Index explains why routers are allowed to draw more on standby than most devices.
What we found when we read 20 Amazon personal alarm listings
Many families buy an alarm for an older relative on Amazon rather than through a monitored service. On 28 October 2026 we read the first 20 unsponsored results for "personal alarm for elderly" on amazon.co.uk: the title, the bullet points, the description and the specification tables of each one.
- 12 of the 20 are pagers. The button rings a receiver inside the same home. They do not call anyone outside it. One of them is titled "Alert Button That Calls Family"; its own description says the receiver "plugs directly into a UK socket".
- 8 of the 20 use Wi-Fi. They send an alert to a phone app through the home router.
- None use a SIM or the mobile network, and none connect to a 24-hour monitoring centre.
- None of the 8 Wi-Fi alarms say what happens in a power cut or when the router is down.
- None of the 20 mention the digital switchover.
Prices ran from £9.99 to £48.99. The finding is that not one of the 20 can contact anyone outside the home in a power cut. The 12 pagers never could. The 8 Wi-Fi models depend on the same router that a digital phone line depends on, so they fail at the same moment it does. If the person you are buying for lives alone, compare these against the monitored, SIM-based alarms in our personal alarms guide.
If you or a relative uses telecare
- Tell your phone provider. BT has a webform to register additional needs, and says around two million of its customers depend more than most on their landline.
- Let the engineer in. BT's own advice is "Don't turn away the engineers": an Openreach engineer reconnects the telecare device and tests it before leaving.
- Test the alarm yourself after the switch, and again after any power cut.
- Ask for the free battery backup unit or hybrid phone if you qualify.
- If the alarm is old and plugs into the phone socket, price a SIM-based replacement now, before the deadline rush. Our guide to helping an elderly parent stay safe at home covers the wider checklist.
The questions that come up most
Will the switchover cost me anything? Usually not. BT says customers "move to Digital Voice for the same price". The costs come if you are not eligible for free backup and want more than a charged mobile, or if an old alarm or fax needs replacing.
Do I need a new phone? Usually not. BT says over 99% of phones work on Digital Voice. A phone in another room needs an adaptor.
Do I have to get broadband? No. BT moves landline-only customers at the exchange, and GOV.UK says a landline-only option remains.
Will my landline work in a power cut? On broadband Digital Voice, only if the router has battery backup, and the guaranteed minimum is one hour. On BT's landline-only route, BT says phones work in a power cut if they do today. Cordless phones have never worked in a power cut.
What if my telecare alarm stops working? BT says its engineer switches you back to analogue until you have a compatible device. Contact your telecare provider as well as your phone provider.
Sources
- GOV.UK, UK transition from analogue to digital landlines (page last updated 28 February 2024), read 28 October 2026
- Ofcom, Protecting customers during the migration to digital landlines (23 January 2024), read 28 October 2026
- BT, Digital Voice stakeholder pack, June 2026 (as published by Amble Town Council), read 28 October 2026
- Which?, Five things you need to know about the landline switchover (27 February 2025)
- ISPreview, Gov asks UK broadband ISPs to offer 8 hours of battery backup (10 September 2024)
- EE, Battery Back Up Plus (Digital Voice), price read 28 October 2026
- Age UK Personal Alarms, Will my personal alarm work after the digital switchover? (5 June 2025)
- Amazon UK search results and listings for "personal alarm for elderly", first 20 unsponsored results, read 28 October 2026
What this guide could not check
- Switchover dates for providers other than BT. Sky, Virgin Media and TalkTalk run their own programmes.
- Battery backup prices and run times from Sky, Virgin Media and TalkTalk. None we read publishes a run time in hours.
- What alarm companies charge to move a burglar alarm or telecare unit off the phone line.
- Whether any individual alarm in our Amazon sample would keep working in a power cut. We read what the listings say; we did not test the devices.
Changes to this page
- 28 October 2026: page published.