Power cut guide
Will My Phone, Broadband and Landline Work in a Power Cut?
Quick answer: A charged mobile phone will usually keep working in a power cut, as long as the local mast has power. Broadband and digital landlines will stop unless your router has a battery backup, and cordless phones need mains power too. If you rely on your landline, for example because you have no mobile signal or use a telecare alarm, your provider should offer a solution such as a battery backup giving at least an hour of emergency calls, free of charge if you are at risk.
Is the power off where you are? See live power cuts from the network operators and reports from neighbours.
Most of the UK is moving from old copper phone lines to digital landlines, and that changes what happens when the lights go out. This guide explains which devices keep working, what your phone provider has to offer, what to do if someone in your home uses a personal alarm, and how to make sure you can always reach 105 and 999.
What works and what does not in a power cut
| Device or service | Works in a power cut? | Why |
|---|---|---|
| Mobile phone | Usually, if charged and the local mast has power | Runs on its own battery; masts may have limited backup |
| Digital landline (phone plugged into router) | No, unless you have battery backup | The router and sometimes a fibre box need mains power |
| Traditional corded phone on an old copper line | Usually yes | Powered from the telephone exchange, which has backup power |
| Cordless phone (any line) | No | The base station needs mains power |
| Broadband and Wi-Fi | No, unless you have battery backup | The router needs mains power, and so does local network equipment |
| Telecare or personal alarm | Depends on the device | Many have a battery, but those on a digital line may need extra backup |
Ofcom’s advice is to keep a mobile phone as a backup, keep it charged, and use it now and then so you know it still works.
The digital landline switchover and power cuts
The old copper telephone network, known as the PSTN, is being switched off across the UK. GOV.UK says most customers are expected to have moved by the end of January 2027, although some providers may work to a different timetable. Telephone providers are moving customers to digital landlines, sometimes called Digital Voice or VoIP, which carry calls over a broadband connection.
The difference that matters in a power cut is simple. Copper lines carried a small electrical current from the exchange, so a basic corded phone kept working. Digital lines cannot carry power, so your handset only works if your router, and your fibre box if you have one, are still powered.
GOV.UK advises asking your provider when your line will be moved if you have not heard yet, and providers should contact you before the switch. Do not confuse those letters or calls with marketing.
Tip: If you still have a copper line, keep a basic corded phone plugged in or easy to reach. It may keep working when your cordless phone does not.
Your right to emergency access in a power cut
Ofcom rules say providers must take all necessary measures to make sure customers can call the emergency services during a power cut. Ofcom’s guidance, which dates from 2018, says providers should:
- have at least one solution that gives access to emergency services for a minimum of one hour in a power cut, such as a battery backup unit;
- take steps to identify customers who are at risk because they depend on their landline, such as people with no mobile signal at home, people who do not use a mobile, or people who use telecare;
- offer that solution free of charge to customers who are at risk;
- explain to all customers that digital landlines need power, and how to get a solution if they need one.
An hour is a minimum, not a guarantee that you will be connected for the whole of a long power cut. Treat it as a way to call for help, not as a full backup for everyday use.
How to ask for battery backup
- Contact your landline provider and say you rely on your landline in a power cut.
- Explain why: no or poor mobile signal at home, no mobile phone, a telecare alarm, or a health condition or disability.
- Ask what solution they offer, how long it lasts, and whether it covers both the router and the phone.
- Ask how to check and replace the batteries, and who to call if it fails.
If you want longer backup or your Wi-Fi too, our guide on how to keep your Wi-Fi on in a power cut explains the options and how to estimate running time.
Telecare and personal alarms
Telecare includes pendant alarms, fall detectors and other devices that call a monitoring centre for help. Many older systems were designed for copper lines, so the switch to digital needs care.
In December 2023, major phone providers signed a charter of commitments to protect telecare users and other vulnerable customers during the move to digital. Network operators including Openreach signed a similar charter in March 2024.
- Tell your phone provider that someone in the home uses telecare, before your line is switched.
- Ask your alarm provider whether the device works on a digital line and in a power cut. You may need an upgrade, a unit with its own battery, or one that uses the mobile network.
- Test the alarm after any change to your line, and ask how long it runs on battery.
- Check the base unit’s battery regularly, following the provider’s advice.
If anyone at home relies on equipment that needs electricity, read our guide to medical equipment and power cuts and make a written plan.
Safety: If a telecare alarm or medical device stops working in a power cut and someone is in danger, call 999 from a mobile. Do not wait for the power to come back.
Will my mobile work in a power cut?
Usually, for a while. Your phone runs on its own battery, but the local mast needs electricity. Some masts have backup batteries, but Ofcom has said there is no explicit minimum backup time set for mast sites, so how long signal lasts varies. In a short local cut you may notice no difference. In a long cut across a wide area, signal can fade or disappear.
Two useful facts:
- You can call 999 or 112 on any mobile network, even if your own network has no signal. Your phone may show “Emergency calls only”.
- 105, the free power cut number, works from mobiles as well as landlines in England, Scotland and Wales.
Our guide to calling 105 explains what happens when you report a power cut.
Keeping your phone charged
Your phone is your torch, radio, map and lifeline, so protect its battery from the moment the lights go out.
- Keep a fully charged power bank in your emergency kit and top it up every few months.
- Turn on low power or battery saver mode straight away.
- Dim the screen and close apps you are not using.
- Use a separate torch rather than the phone’s light.
- Send texts rather than making long calls; they use less battery and often get through when calls struggle.
- Charge from a car only with the car parked outdoors. Never run an engine in a garage.
Write down important numbers on paper too, including 105, your network operator and family. Our emergency numbers page lists them in one place.
Contacting 999 if you are deaf or have difficulty speaking
If you cannot use a voice call, there are other ways to reach the emergency services. Set them up before you need them.
emergencySMS
emergencySMS lets deaf, hard of hearing and speech-impaired people text 999. You must register your mobile first:
- Text the word “register” to 999.
- Read the reply carefully and answer “yes”.
- Wait for a text confirming you are registered.
You will need to register again if you change your number. Relay UK advises using it only if you have no other option, because texts are slower than a call, and replies can take a couple of minutes. In a message, say which service you need, what is happening and exactly where you are.
Relay UK and BSL
You can also contact 999 through Relay UK by dialling 18000, and British Sign Language users can use the 999 BSL video relay service. Both need a working data or phone connection, so keep your phone charged.
Get extra help from the Priority Services Register
If you are older, disabled, have a long-term health condition, rely on medical equipment or have young children, you can join the Priority Services Register for free. In a power cut, your network operator can give you priority updates and, in long cuts, extra support where available. Our guide to the Priority Services Register explains how to join.
Being on the register for electricity does not tell your phone provider you need a battery backup. Contact them separately.
Frequently asked questions
Will my landline work in a power cut?
If it is a digital landline that plugs into your router, no, unless you have a battery backup. A basic corded phone on an old copper line usually keeps working. Cordless phones stop in either case.
Do I have to pay for a battery backup for my digital landline?
Not if you are at risk because you depend on your landline, for example with no mobile signal at home or a telecare alarm. Ofcom guidance says providers should offer a solution free to these customers. Others may be offered one at a cost.
How long does a landline battery backup last?
Ofcom’s guidance sets a minimum of one hour of access to emergency services. Some units last longer, so ask your provider for the figure for yours.
Can I still call 999 if my mobile has no signal from my network?
Yes, if any other network has signal where you are. Emergency calls to 999 or 112 can use any available mobile network.
When is the copper landline switch-off?
GOV.UK says most customers are expected to have moved to digital landlines by the end of January 2027, though not every analogue service will be switched off by then. Your provider should contact you before moving your line.
Your next step: check what kind of landline you have, and if anyone at home relies on it, call your provider this week to ask about battery backup. Then charge a power bank and put it with the rest of your power cut emergency kit, so you are ready whichever way the power cut goes. If the power is off now, check your postcode for live updates.
Sources
- Ofcom u2013 Landlines and power cuts
- GOV.UK u2013 UK transition from analogue to digital landlines
- Ofcom u2013 Protecting customers during the migration to digital landlines
- Ofcom u2013 FOI response: power backups and the switch to digital voice
- Relay UK u2013 Contact 999 using Relay UK and emergencySMS
- ISPreview u2013 New guidelines on accessing emergency services via broadband VoIP (Ofcom 2018 guidance)
- Be Ready (UK Government) u2013 Power cuts
Checked against these sources on 28 October 2026. Rules and amounts can change – your network operator or Ofgem has the final word. Spotted something out of date? Tell us.
More on being prepared: Power Cut Emergency Kit: What to Keep at Home · All power cut guides