The UK will switch off its traditional PSTN and ISDN telephone services on 31 January 2027.
If your business still uses analogue phone lines, an ISDN connection or equipment that relies on these services, you will need to arrange a suitable digital replacement.
This includes more than office phones: alarms, lift emergency telephones and older payment terminals may also need upgrading.
| Factors | PSTN Switch-Off At A Glance |
|---|---|
|
Switch-Off Date |
31 January 2027, with no extension planned |
|
What Is Switching Off? |
Analogue phone lines (PSTN) and ISDN, including ISDN2 and ISDN30 |
|
Lines Still On Copper |
About 1 million, including about 300,000 business premises (Openreach) |
|
Lines Already Moved |
About 15 million since 2017 |
|
Also Affected |
Broadband that runs over a copper phone line (ADSL, FTTC and G.fast) and devices such as alarms and card machines |
|
What Replaces It? |
Digital calls over the internet: a VoIP phone system, SIP trunks or a digital phone line |
Key Takeaways
The PSTN switch-off date is 31 January 2027. The national shutdown of traditional phone lines and ISDN won’t be delayed again.
There is not much time left. In Openreach’s latest update, about 300,000 business premises were still using the old copper network.
Staying on analogue is getting pricier. In 2026, Openreach raised wholesale line rental three times, almost doubling 2025 rates.
It is not only your phones. Security alarms, lift lines, card machines, CCTV and fax machines may also depend on a phone line.
You can keep your phone numbers. Most businesses move to a VoIP phone system and port their existing numbers across.
Use ComparedBusiness UK to find the top VoIP providers for your switch.
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What Is The PSTN Switch-Off?
The PSTN switch-off retires the UK’s old copper telephone network. All landline calls will move to digital technology that carries calls over an internet connection, known as VoIP (Voice over Internet Protocol).
The PSTN (Public Switched Telephone Network) is the analogue network that has carried landline calls in the UK for many decades.
ISDN (Integrated Services Digital Network) is an older digital service that uses the same network. Many businesses use ISDN for multi-line phone systems. Both are being switched off.
According to Ofcom, the PSTN is ageing and is getting harder and pricier to maintain. The telecoms industry, not Ofcom or the government, is leading the switch, but Ofcom has set rules to protect customers during the process. Openreach, which runs most of the UK’s phone network, is carrying out the switch-off.
To learn more about the technology, read our guides to what VoIP is and VoIP vs landline phones.
When Is The PSTN Switch-Off? Key Dates
The PSTN switch-off date is 31 January 2027. The plan was first announced in 2017, targeting the end of 2025, but was later pushed back to January 2027. Openreach has said there will be no further extension.
| Date | What Happens |
|---|---|
|
November 2017 |
The industry announces plans to retire the PSTN and ISDN services. |
|
December 2023 |
Phone providers sign a charter to protect telecare users and other vulnerable customers. |
|
April 2026 |
Openreach raises wholesale rental on legacy lines by 20%. |
|
July 2026 |
A further 40% rise. |
|
October 2026 |
A final 40% rise, roughly doubling the 2025 rental. |
|
31 January 2027 |
The PSTN and ISDN close. |
|
After 31 January 2027 |
Lines that have not moved go onto an emergency product or are ceased in stages. |
Your provider may contact you before the national date, but it is best not to wait for that letter. Moving takes time, especially if you have several sites or connected devices.
How Many Businesses Still Need To Switch?
In Openreach’s latest update, it is estimated that around 1 million lines were still operating on the old copper-based phone network, including approximately 300,000 business premises. Around 15 million lines have been migrated since the closure was announced in 2017.
James Lilley, Openreach’s Director of All-IP, has said the straightforward migrations are ‘largely completed’. The lines that remain are often the complex ones, such as alarm, lift and payment lines that support critical operations. These need extra planning and testing, which is why it pays to start early.
The ISDN Switch-Off: What ISDN2 And ISDN30 Users Need To Know
The ISDN switch-off happens on the same date as the PSTN switch-off: 31 January 2027. Both ISDN2 (usually two channels for small offices) and ISDN30 (up to 30 channels for larger phone systems) will stop working.
What you do next depends on your phone system:
- You want to keep your existing phone system (PBX): Replace your ISDN lines with SIP trunks, which connect your PBX to the phone network over the internet. Check with your PBX supplier that the system supports SIP.
- Your phone system is old or due for renewal: Move to a hosted VoIP system, where your provider runs the phone system in the cloud, and you only need phones or apps. Find out more in our comparison of hosted vs on-premises VoIP.
For a detailed side-by-side comparison, see our guide to VoIP vs ISDN.
What Does The PSTN Switch-Off Mean For Your Business?
For most companies, the switch-off affects four areas: phone lines, broadband, costs, and what happens to your phones in a power cut.
1. Your Phone Lines And Number
Traditional phone lines and ISDN will stop working after the switch-off. In most cases, you can keep your business numbers by porting them to your new provider. See our guide to transferring a landline number to VoIP for more details.
2. Your Broadband
Some broadband also relies on the copper line. According to Openreach, standard ADSL, Fibre to the Cabinet (FTTC) and G.fast all use copper for part of the connection.
Where technically possible, Openreach will keep broadband running on a transferred line, but the long-term options are a digital line such as SOGEA (broadband without a phone line) or full fibre.
If your business needs a fast and reliable internet connection for VoIP, compare your options in our guide to leased line vs FTTP.
3. Your Costs
Staying on an analogue line is becoming more costly. Openreach raised the wholesale price that providers pay for legacy lines by 20% in April 2026, 40% in July and another 40% in October. Openreach says the increase roughly doubles rental compared with 2025, and these costs can be passed on to customers.
4. Power Cuts
A traditional corded phone takes its power from the phone line, so it keeps working in a power cut. A digital phone needs mains power and won’t work without a battery backup.
According to GOV.UK, providers should offer at least one way to reach the emergency services for at least one hour in a power cut, free to customers who are at risk. For a business, the simplest backup is usually keeping staff mobiles charged.
Which Devices Does The PSTN Switch-Off Affect?
Any device that relies on a phone line could stop working after 31 January 2027. In February 2026, Openreach reported that it still needed to move more than 12,000 lift lines and about 500 CCTV lines. Check every device on this list:
| Device | Why It Is Affected | What To Do |
|---|---|---|
|
Burglar and Fire Alarms |
Many alarms send signals to a monitoring centre via a phone line. |
Ask your alarm company whether it works over VoIP or needs a 4G or digital upgrade. |
|
Lift Emergency Telephones |
Lift alarms often use a dedicated analogue line. |
Ask your lift maintenance company for a digital or mobile replacement. |
|
Card Machines and Payment Terminals |
Older terminals connect over a phone line. |
Switch to a terminal that uses broadband, Wi-Fi or mobile data. |
|
Fax Machines |
Fax relies on analogue lines. |
Move to email or an online fax service. |
|
CCTV Systems |
Some use phone lines for remote monitoring. |
Check with your installer. |
|
Telecare and Health Alarms |
Pendant alarms often call out over the phone line. |
Tell your telecare provider, and test the device after switching. |
|
Vending Machines and Smart Meters |
Some report readings or sales over a phone line. |
Check with the supplier or operator. |
Some older devices can work on a digital line using an adapter. You can learn more in our guide to what a VoIP adapter is.
What Are Your Options After The Switch-Off?
Every business needs a digital replacement for its analogue phone lines. Here are your options:
| Option | How It Works | Best For |
|---|---|---|
|
Cloud (hosted) VoIP Phone System |
Calls run over your internet connection, and the provider hosts the phone system. You use desk phones, a computer, or a mobile app. |
Most small and medium businesses, as well as remote and hybrid teams, use this service. |
|
SIP Trunks |
Connect your existing on-site phone system (PBX) to the network over the internet. |
Businesses with a modern PBX they want to keep are often ISDN30 users. |
|
Digital Phone Line From Your Provider |
Your provider moves your line to a digital service, often with a new router. |
Very small businesses that need one or two simple lines. |
|
Mobile Only |
Staff use business mobiles instead of landlines. |
Sole traders and teams that are always on the move. |
For most companies, a cloud phone system is the most flexible option. It works wherever there is an internet connection, and you can add or remove users as your business grows.
Read our list of the best cloud-based phone systems and our guide to what equipment is needed for VoIP.
How To Prepare For The PSTN Switch-Off: 7 Steps
GOV.UK advises businesses to talk to their provider, review every device that relies on a phone line, and move to digital early to avoid disruption. Follow this checklist:
1. Find all your lines. Check your phone bills for every analogue line and ISDN channel at each site.
2. List every connected device. Include alarms, lift phones, card machines, CCTV, fax machines and telecare devices.
3. Review your contracts. Note when each line and phone system contract ends and any early exit fees.
4. Check your broadband. VoIP needs a stable connection. If yours is slow or unreliable, plan an upgrade before you switch. Read our guide on whether VoIP is reliable.
5. Choose your new provider and port your numbers. Compare VoIP or SIP providers and ask how long porting takes.
6. Test everything. After the move, test alarms, lift phones, and payment terminals with each supplier.
7. Plan for power cuts. Decide how staff will call for help if the power goes off, for example with charged mobiles or a battery backup.
What Happens If You Do Nothing?
If you don’t move before the deadline, your lines and the devices that rely on them will stop working. Openreach has set an emergency rental of £35 a month (wholesale) for a basic line that has not moved and says lines that cannot be transferred to that product will be ceased in stages.
If you have not moved by 31 January 2027, eligible lines may be transferred to Openreach’s Emergency Voice and Access Continuity (EVAc) service. This temporary, limited service costs communications providers £35 per month for WLR3 Basic or £38.60 for WLR Premium.
It is intended as a temporary measure, not a permanent replacement. Lines that cannot be transferred may be ceased in stages. You will still need to arrange a suitable digital service.
In practice, that means higher bills first, then lost phone lines, alarms that can’t reach their monitoring centre, and card machines that can’t take payments. Moving on your schedule is cheaper and far less disruptive than a last-minute move.
How Much Does It Cost To Switch To VoIP?
Business VoIP in the UK costs about £7 to £40 per user per month, depending on the plan. Desk phones start from about £40, or staff can use a free app on their computer or mobile instead. Number porting is usually free.
For detailed prices by team size, see our guide to VoIP phone costs and our VoIP vs landline cost comparison.
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FAQs
No, in most cases, you can usually port your existing numbers to your new VoIP or digital line provider.
Broadband services such as ADSL and FTTC run over a copper phone line, so they depend on the old network. Openreach will keep them running where technically possible, but you should plan to switch to a digital line or full fibre.
Yes. The ISDN switch-off happens on the same date, 31 January 2027. ISDN2 and ISDN30 users usually move to SIP trunks or a hosted VoIP system.
A digital phone needs a power supply, so it won’t work in a power cut without a backup battery. Providers should offer at-risk customers a way to make emergency calls for at least one hour during a power cut.
