If your business still has a traditional phone line, a fax, a card terminal plugged into a phone socket, or an alarm that "dials out", this affects you. The analogue public switched telephone network (PSTN) — the copper phone network the UK has used for more than a century — is being switched off on 31 January 2027. That date was pushed back once already (from December 2025) and Openreach has been clear there will not be another delay.
This is not a scare story and it is not a sales pitch for a shiny new system. It is a fixed engineering deadline, and the sooner you deal with it the cheaper and calmer it is.
What is actually being switched off
Two things are going:
- PSTN — the analogue voice network your phone number has historically lived on.
- ISDN — the digital lines (ISDN2 and ISDN30) that many offices used for their phone systems.
Everything that used to ride on those lines moves to an internet-based (all-IP) service instead. Your broadband will still work, but the voice part of the line disappears. Openreach stopped selling new analogue lines back in 2023 (the "stop-sell"), so anything you have now is legacy kit living on borrowed time.
Why waiting costs money
In February 2026 Openreach reported that around 2.8 million lines still had to migrate, more than 500,000 of them serving business premises. To push the stragglers along, the wholesale rental for the old products is being increased in three steps during 2026 — in April, July and a final rise on 1 October 2026. Your provider passes those costs on. In other words, a line you keep until the last minute costs noticeably more every quarter, and then simply stops.
There is a second, quieter cost: engineer availability. Everybody who has not moved will be trying to book installations in the same few weeks. Book now and you pick the date; book in January and you take what is left.
What stops working on the day
The obvious one is the desk phone plugged straight into the wall socket. The less obvious ones are the things nobody thinks about until they are silent:
| Equipment | Typical problem | What to do |
|---|---|---|
| Intruder or fire alarm with a dial-out panel | Stops reporting to the monitoring centre | Ask your alarm company for an IP or 4G communicator |
| Card payment terminal (PDQ) on a phone socket | Cannot authorise payments | Move to a Wi-Fi, Ethernet or 4G terminal |
| Fax machine | No dial tone | Switch to email-to-fax, or retire it |
| Lift emergency phone | Trapped-passenger line goes dead — a safety issue | Lift maintainer must fit a digital or GSM unit |
| Door entry / gate intercom | Cannot call out | Replace with an IP or SIM-based intercom |
| Franking machine, older CCTV DVRs, telecare pendants | Silent failures | Check each one with the supplier |
| Analogue phone system (PBX) on ISDN | Whole system loses its lines | Move to a hosted VoIP system, or add a SIP gateway |
The trap is that most of these will fail silently. Nothing beeps, nothing flashes; they just stop reporting. That is why the first job on the checklist is an inventory, not a purchase.
The checklist
- List every socket and every device. Walk the building. Note everything plugged into a phone socket, and every device that "phones home" — alarms, lifts, terminals, intercoms, meters. Photograph labels.
- Find out what you actually pay for. Your phone bill will list the lines (they may be called WLR, PSTN, analogue, ISDN2e or ISDN30). Many businesses discover lines they forgot existed and have been paying for since a previous tenant.
- Decide where the voice service goes. For almost every business of 2–500 people the answer is a hosted VoIP system: your numbers move to the cloud, calls run over your broadband, and the handsets (or an app on your mobile) connect over the network. There is no box in the cupboard to maintain.
- Check the broadband can carry it. A good VoIP call needs roughly 100 kbit/s in each direction with low jitter. Almost any fibre connection is fine; a congested or ageing ADSL line may not be. We test this before we quote, never after.
- Keep your numbers. Numbers are ported, not lost. Do not cancel the old line yourself — cancel it and the number can go with it. The new provider ports first; the old service is ceased afterwards.
- Sort the special devices. Alarm, lift and payment kit is handled by the company that maintains it. Give them the date and ask in writing what they will fit. Get the answer before you book the voice migration so both happen in the right order.
- Plan for power cuts. An old analogue phone kept working when the electricity failed. VoIP does not, unless the router and phone have battery backup. Ofcom requires providers to offer a solution for customers who rely on the line for emergency calls; for a business a small UPS on the router is the usual answer.
- Train the team for ten minutes. New handsets and apps behave slightly differently — transfers, voicemail, out-of-hours rules. Ten minutes on the day saves a week of grumbling.
What a well-run migration looks like
From the customer's side it is dull, which is the point. Numbers are ported on a chosen day (usually mid-morning, mid-week, so any issue is found while support desks are fully staffed). Handsets have been on desks and tested for a few days beforehand. The old line is ceased a week or two later, once everyone is sure nothing else was hanging off it. The alarm and payment terminal were switched earlier, independently, so nothing depends on everything happening at once.
If a supplier proposes doing all of it on the same afternoon, ask why.
Home users are affected too
The same switch-off applies to home phones. If you or an older relative relies on a landline — especially with a telecare pendant or a phone-line alarm — the provider should be moving you to a digital voice service and must take extra care with vulnerable customers. We wrote about that separately for home users; the short version is that the handset usually plugs into the back of the router instead of the wall.
The honest summary
You do not need the most expensive system, and you do not need it today. You do need to know what is on your lines, and you need a date in the diary well before January. The businesses that find the switch-off painful are the ones who discover their alarm or card machine was on an analogue line the morning after it stopped.
If you would like an engineer to do the inventory with you and tell you plainly what needs to change — and what does not — that is exactly the kind of conversation we are set up for. See our VoIP and landline switch-over page for how we approach it.