Openreach closes the analogue phone network at the end of January 2027, and around 350,000 UK business premises are still running on copper. ISDN2 and ISDN30 circuits have no migration path, so those customers face a harder deadline than the coverage suggests.
PSTN switch-off: 350,000 UK business premises are still on copper
Openreach switches off the PSTN at the end of January 2027, and it now estimates around 1.5 million lines are still running on the old copper network nationwide, including around 350,000 business premises. If one of those lines is yours, you have about four months. If any of them is an ISDN2 or ISDN30 circuit, you may have less room than that, because a senior Openreach manager has said those circuits have no migration path at all.
Where the remaining lines are
Openreach published a city-by-city breakdown on 17 September 2026 showing how much legacy kit each major UK city has left to shift. Liverpool is furthest ahead with 6.35% of its legacy lines still to convert. London has the most left at 12.92%.
City Legacy lines left to convert Liverpool 6.35% Manchester 7.35% Sheffield 7.55% Cardiff 8.35% Leeds 8.62% Edinburgh 8.82% Bristol 8.99% Birmingham 9.08% Glasgow 10.60% London 12.92%
Bristol sits seventh of the ten at 8.99%, with Birmingham just behind it at 9.08%. Across those ten cities and the areas around them, Openreach says around 90% of legacy lines have already moved.
Read that carefully, because the percentages describe cities rather than companies. A city being 91% done tells you nothing about whether your building sits in the 9% that isn't. It does tell you the remaining lines are now unusual, and unusual lines get less attention from suppliers working through a queue.
What changed since we last wrote about this
We published a guide to VoIP providers for small businesses in August, and it quoted Openreach's February 2026 position: roughly 2.8 million lines still to migrate, with more than half a million of them serving business premises.
Seven weeks later those numbers are 1.5 million and 350,000. Around 150,000 business premises came off copper in under two months, and the lines left behind are increasingly the ones nobody has got round to.
The cost of waiting went up three times this year
Openreach raised the basic rental on Wholesale Line Rental, the copper product most analogue business lines sit on, by 20% on 1 April 2026 and by a further 40% on 1 July. Another 40% lands on 1 October. Openreach says the sequence effectively doubles the rental cost of a legacy line against 2025 rates, from a basic rental of £10.65 set out in its November 2025 pricing release.
Your provider may not pass each rise straight through, and the timing of when it reaches your bill depends on your contract. A line you keep because moving it feels like a hassle is getting more expensive on a schedule Openreach has already published, and the last of those increases is days away rather than months.
The circuits with no way forward
Juliette Scott, Openreach's senior manager for all-IP migrations and exchange exit, gave an interview to Zen Internet in June 2026 that was reported by ISPreview. She said there won't be a "big bang" on 1 February 2027 for everyone, and that lines which haven't moved will be shifted onto a stopgap product called Emergency Voice Access. On ISDN2 and ISDN30 she was more direct: those customers "don't have a path … so from 1st February they will be ceased".
That quote comes from an interview rather than a published Openreach document, and we couldn't find the same statement anywhere on Openreach's site, so treat it as a senior Openreach manager's description rather than formal policy. It is corroborated from a different direction, though. ISPreview's separate April briefing on the Emergency Voice Access pilot states that the product won't carry broadband, ISDN or critical alarm and lift signals.
Emergency Voice Access is real, and Openreach began piloting it from 3 August 2026 in the Salisbury and Mildenhall exchange areas. It carries voice and nothing else, so a line moved onto it loses any broadband riding on the same circuit. Lines that communications providers have flagged as critical national infrastructure or as serving vulnerable customers are handled through separate processes.
Why four months is tighter than it sounds
If your business runs an ISDN30, the circuit is rarely the expensive part. An ISDN30 normally sits underneath a phone system bought before it, and older systems often can't take a SIP connection without being replaced. Replacing the circuit then means replacing the phone system with it.
A platform project has a shape that doesn't compress well. You choose a supplier, which means comparing quotes that describe different things. You port your numbers, and porting is the step that runs to someone else's timetable rather than yours, because it involves your losing provider as well as your new one. You configure call routing, and the rules for who picks up out of hours usually live in one person's memory rather than in a document. Then you put handsets or headsets in front of people who were perfectly happy with the old ones.
Porting runs to your losing provider's timetable, and the rest of the work queues behind it. That competes badly with everything else in a small business's autumn, and the businesses that find this uncomfortable in January will mostly be the ones that started looking in December.
What else runs over these lines
Openreach lists far more than telephones running over the copper network: payment terminals and lift alarms, security systems, door entry systems and building management technology.
These are the connections that get missed, because none of them has an obvious owner. Your phones belong to whoever answers them. A lift emergency phone belongs to the lift maintenance contract, which sits with facilities, which may sit with your landlord. A card terminal belongs to finance. The alarm belongs to whoever signed the monitoring agreement, possibly a decade ago. When the network goes, all of them stop working, and each one has a different person to call about it.
The landlord point deserves a moment if you rent. A lift line or a door entry panel in a shared building is often the freeholder's contract, not yours, which means the person who has to act isn't in your organisation. That's a longer conversation than a supplier call, so it's worth starting early even if the answer turns out to be that somebody else has it in hand.
Government guidance on the analogue to digital transition puts the responsibility where it lands: "Communications providers will not know which devices are connected to their network, and therefore it is important for business customers to review which devices they are using and determine whether they need replacing or upgrading, or whether adaptors might be required." Your provider cannot do this survey for you, because it cannot see what you plugged in.
Digital lines and power cuts
One difference between the old network and the new one catches businesses out after the migration rather than during it. An analogue line drew its power from the exchange, so it kept working when the building lost electricity. A digital line does not. The government guidance states that digital landlines "will not function in a power cut unless you have a backup power system", because handsets and routers run off your own supply.
There is a safety net, and it is narrower than it sounds. Providers must take measures to ensure uninterrupted access to emergency services, and the guidance says they should have at least one solution giving access to emergency organisations for a minimum of one hour during a power cut, offered free of charge to those at risk. That is access to 999 for an hour for people who qualify. Your phone system, card terminals and door entry panel are outside that guarantee. If your building needs any of them during an outage, a battery or a mobile fallback is a separate decision you make yourself.
What to do this week
Walk the building and write down everything plugged into a phone socket, including the sockets in cupboards, plant rooms and lift lobbies. Every quote and every migration plan starts from that list.
Then ask your communications provider, in writing, which of your circuits are analogue and which are ISDN. Ask for the answer per circuit rather than per site, because a site summary hides exactly the circuit you're trying to find. A written answer gives you something to act on, and it puts the question on record with the supplier whose queue you're now in.
If both answers come back clean, meaning nothing in the building runs over a phone line and none of your circuits is ISDN, you're finished and you can stop thinking about this. Asking is how you find out if your business is one of the exceptions.
If the answers aren't clean, you then decide what replaces the lines, and our VoIP provider comparison sets out the UK options with published pricing. Ofcom regulates the migration, and the government guidance linked above covers the same ground for business customers.
Where we can help
Inflection Point runs IT consultancy for UK businesses of 10 to 500 staff, and a switch-off audit is a small piece of work. We establish what you have, what it's connected to and what each item needs, then tell you whether there's a project here or nothing to worry about.
If you'd like a second pair of eyes on your list before January, book a discovery call and we'll go through it with you.
