PSTN Switch-Off 2027: A Checklist for UK Businesses

The PSTN switch-off is 90 days away, and Openreach says the date will not move. On 31 January 2027 the UK's copper landline network (the public switched telephone network, or PSTN) is retired, and every phone line, alarm line and card machine still running on it has to be on a digital connection by then. If your business still has any analogue or ISDN lines, the short answer is: list everything plugged into them this week, book the migration with your provider this month, and use the move to fix how your calls get answered, because you will never have a cheaper moment to change your phone setup.

Most guides stop at "switch to VoIP". This one covers what actually breaks, the order to do things in, what to ask your provider, and why the switch-off is the right time to put an AI voice agent on the line.

What Openreach Announced

Openreach, BT Group's network business, has written to the communications providers that sell on its network to warn that the 31 January 2027 deadline is final, as reported by The Register on 1 November 2026 (theregister.com/networks/2026/11/01/landline-phones-will-switch-off-across-britland-in-100-days-no-extensions-openreach/5306673). Three points matter for a business owner:

• No extension. The switch-off has been planned for nearly a decade and was already pushed back once to protect vulnerable telecare users. Openreach's Director of All-IP, James Lilley, says "the straightforward migrations have largely been completed." What is left is mostly complex connections tied to critical operations, which is a polite way of saying businesses.
• Waiting is already costing money. Providers and companies still renting legacy business lines are paying double the rental they paid a year ago.
• No fibre is not an excuse. Premises without fibre are expected to move to a transitional Openreach product (SOTAP for Analog) that keeps an existing line working from the exchange. It is a stopgap, not a plan.

What Breaks on 31 January (It Is Not Just the Phone)

The desk phone is the easy part. The lines that catch businesses out are the ones nobody thinks of as a phone line at all:

• Card machines. Older payment terminals that dial out over a landline stop taking payments. Check whether yours use the phone line, broadband or a SIM.
• Fire and intruder alarms. Monitored alarms that signal a receiving centre over the PSTN need a digital or dual-path communicator. Your insurer may require proof the alarm is still monitored.
• Lift emergency phones and door entry systems. Many still use an analogue line. Your lift maintenance contractor and building manager need to sign these off.
• Telecare and personal alarms. Critical for care providers and anyone with lone workers.
• Franking machines, fax lines, CCTV dial-outs and old telemetry. Rare now, but each one is a line someone pays for and nobody remembers.
• ISDN phone systems. If your office PBX runs on ISDN30 or ISDN2 lines, the whole phone system needs replacing or re-connecting through SIP trunks, not just the handsets.

A 90-Day PSTN Switch-Off Checklist

Hardware lead times grow as the deadline gets closer, so work in this order:

1. 1Weeks 1 to 2: Inventory. List every line, what it connects to, who owns it and which provider bills for it. Include branches, warehouses and any site with a lift, alarm or card machine.
2. 2Weeks 2 to 3: Call your providers. Ask for each line's migration date, the replacement product and whether your provider has set an earlier cut-off than Openreach (some have). Get it in writing.
3. 3Weeks 3 to 6: Replace the non-phone equipment first. Alarm communicators, card terminals and lift lines depend on third-party engineers, so book them before the January rush. Openreach offers free compatibility testing of equipment at its test labs if you are unsure.
4. 4Weeks 4 to 8: Choose your new phone setup. A cloud phone system (hosted VoIP) for most small and mid-sized businesses, or SIP trunks if you are keeping an on-premise PBX. Port your existing numbers; never let a provider talk you into new ones.
5. 5Weeks 8 to 10: Decide how calls get answered. Opening hours, call routing, voicemail, overflow and after-hours handling all get set up from scratch on a new system. This is where the AI voice agent decision belongs (more below).
6. 6Weeks 10 to 12: Test and cut over. Test every number, every alarm signal and every card machine on the new connection, with a fallback plan (mobile divert) for the first week.

Why This Is the Right Moment for a Voice AI Agent

Here is the part the telecom providers will not tell you. Moving to a cloud phone system means rebuilding your call flows anyway: who answers, what happens when nobody does, and what happens at 7pm on a Friday. Most businesses copy the old setup across, including the bits that lose them work: a phone that rings out at lunchtime, a voicemail box nobody checks until Monday, a switchboard menu callers hang up on.

Adding an AI voice agent to a digital line is a configuration change, not a hardware project. The agent sits on the number or the overflow route, answers in a natural voice, handles the routine calls (opening hours, booking, order status, quotes, taking a message with the details you actually need) and passes everything else to a person with a written summary. On a legacy analogue line, doing the same means extra kit and call forwarding hacks. On the new system it is a routing rule.

It also fixes a problem the switch-off makes worse. During migration, numbers move, extensions change and staff learn a new system. Calls get missed. An agent that answers every overflow and after-hours call means the switchover week does not become the week you lost ten enquiries to a competitor. For how AI systems are starting to call businesses on customers' behalf, and why an unanswered line now loses more than one caller, see wizeb.com/blog/google-agentic-calling-business-phone-readiness-2026.

Example: A 25-Person Heating Engineers Firm in Leeds

Consider a heating and plumbing company in Leeds with 25 staff. This is an illustrative example, but the setup is typical. It has an ISDN2 line feeding an old office phone system, two analogue lines for a monitored alarm and a fax nobody uses, and a card machine at the trade counter. Its provider has written twice about the switch-off; nobody has replied.

The inventory finds four lines, not two: the fax and an old broadband line are still being billed. The firm cancels both, books an alarm communicator upgrade, moves the card machine to broadband with a 4G backup, and ports its main number to a cloud phone system. Then it looks at its call logs and sees the real cost of the old setup: the office phone goes unanswered whenever both coordinators are on calls, and emergency boiler calls after 5pm go to voicemail.

So it adds a voice agent on the overflow and after-hours route. The agent takes the caller's name, postcode, boiler make and fault, checks whether it is an emergency against rules the owner wrote, texts the on-call engineer for emergencies and books routine visits into the job calendar. A person still handles quotes and complaints. The phone system project was happening anyway; the agent was one extra line item on it.

What to Ask Before You Add a Voice Agent

• Does it work with the phone system we are moving to, or does it force us onto the vendor's own system? You want one that sits on any SIP or cloud line.
• Can it read and write to our real systems (calendar, CRM, job management) or does it just take messages?
• What does it do when it is unsure? A good agent hands over to a person with a summary; a bad one guesses.
• Where are call recordings and transcripts stored, and for how long? Under UK GDPR you need a lawful basis and a retention period, and callers should be told they are speaking to an AI.
• What does it cost at our real call volume, per month, all in?

If a voice agent is your first AI project, our guide to picking one at wizeb.com/blog/first-ai-agent-for-business shows how to choose the job with the clearest payback, and wizeb.com/blog/sms-ai-agent-for-business covers the text-message side of the same idea. The full playbook for getting an agent live is at wizeb.com/blog/how-to-implement-ai-agents-in-business.

Not in the UK?

Copper networks are being retired in other countries too, on different timelines, and the same order of work applies: inventory every line, replace the alarms and card machines first, then rebuild your call handling on purpose instead of copying the old setup across.

How WizeB Helps

WizeB builds custom AI agents, workflow automations and voice agents for growing businesses in the US, UK and Europe. We are not a telecom provider and we will not sell you lines or handsets. What we do is the part that comes after: we look at your call logs, find the calls you are missing and the ones that do not need a person, and build a voice agent that works on the cloud phone system you are moving to, connected to your calendar, CRM or job system, with clear handover rules. Every project starts with a free scoping call and a fixed price and timeline before any work begins. See how it works at wizeb.com/services/voice-ai.