What the UK landline switch-off means for small businesses

The UK landline switch-off is not the end of business phone numbers or desk phones. It is the retirement of the ageing network beneath many traditional services: the Public Switched Telephone Network (PSTN), together with products that rely on it such as ISDN and some older broadband connections.

Calls are moving to internet-based technology, often described as VoIP, Digital Voice or All-IP. For a small business, the visible telephone may be the easy part. The real job is identifying every alarm, terminal, entry system or other device quietly using the old line—and confirming that it will work after migration.

What is actually being switched off?

The PSTN is the traditional telephone network that has carried calls for decades. Openreach says its parent company, BT Group, will retire that network by 31 January 2027. Legacy Wholesale Line Rental products are being withdrawn, while business voice services move to IP-based alternatives.

The deadline has previously moved, which is why some old material still refers to December 2025. The current date published by Ofcom, GOV.UK, Openreach and BT Business is January 2027. Businesses should not interpret the extension as a reason to wait: migrations are already taking place and older services can become harder or more expensive to maintain.

This is mainly about the technology delivering the service. A familiar geographic number and desk-phone experience can continue, but the call will travel over an internet connection rather than the old analogue network.

Which small-business services could be affected?

Start with the telephone bill, but do not stop there. GOV.UK specifically advises business owners to review infrastructure and devices that depend on PSTN or ISDN. The affected line may have been installed years ago, billed separately or known only to an alarm or maintenance contractor.

An adaptor may make an ordinary telephone work through a router, but that does not prove every specialist device will work reliably. Analogue modems and signalling equipment can be sensitive to the way audio is converted and carried. The equipment provider—not an assumption based on the plug fitting—should confirm compatibility.

Will broadband stop working?

Not every service carried partly over copper ends simply because the analogue phone network closes. For example, SoGEA can provide broadband over fibre to the cabinet and copper for the final section without a traditional phone line. Full Fibre, or FTTP, runs fibre directly into the premises.

However, ADSL and certain services tied to the legacy Wholesale Line Rental network are affected. BT Business lists PSTN, ISDN, ADSL and related analogue services within its switch-off programme. Ask your current provider to identify the exact product—not merely whether the cable entering the building is copper—and confirm its migration route.

Can you keep your business phone number?

In many cases, yes. Your provider should explain whether the number will transfer to its digital service or needs to be ported to another provider. Confirm the number or range of numbers, any hunt groups, call diversions and published caller ID before placing the order.

Do not cancel the old line first. Cancellation can interfere with a number port and may also cease linked broadband or other services. Agree which provider is managing the transfer, the expected date, what happens if the port is delayed and when the old service can safely close.

Could digital call answering help with missed enquiries?

Moving business calls onto digital technology can also be a useful time to review what happens when nobody is free to answer. An AI virtual receptionist can be configured to answer when the team is busy or unavailable, capture the caller's details, follow agreed booking or routing rules and send a summary to the business.

This is a separate choice from the network migration itself. Consider the quality of the setup, the information callers will be asked to provide, privacy arrangements, support and the full contract terms. Explore AI call answering in SME Sorted's value-added services.

For a structured comparison, use the phone, broadband and AI call-answering review guide and its printable workbook.

What happens in a power cut or broadband failure?

A traditional analogue telephone could often draw power from the network. A digital phone normally relies on powered equipment at your premises, such as a router, optical network terminal, network switch, base station or IP handset. If the electricity or data connection fails, calls may fail too unless you have a suitable backup.

For a business, resilience should match the consequence of losing the service. A shop may need mobile data for card payments; a surgery, care setting, lift or monitored alarm can have more demanding safety and continuity requirements. Consumer backup obligations should not be treated as a complete business continuity plan.

Map the whole chain and ask how long each essential component must run. A UPS powering only the router is not enough if the fibre terminal, network switch, phone system or handset also loses power. Consider a tested mobile alternative, call diversion, dual connectivity or an appropriately specified battery backup where needed.

A practical switch-off checklist

1. List every line and number: use bills, wall sockets, equipment labels and contractor records to find services, including rarely used backup lines.
2. Trace connected equipment: check alarm panels, lifts, door systems, payment devices, fax machines and remote-monitoring equipment.
3. Identify the current products: ask the provider whether each service is PSTN, ISDN, ADSL or already All-IP.
4. Contact equipment suppliers: obtain written compatibility advice and the exact upgrade needed. Do not rely on a general promise that “it should work”.
5. Choose the replacement: consider available broadband, number requirements, users, call routing, support and contract terms—not only the monthly price.
6. Plan resilience: decide what happens during a power or broadband outage and test the complete backup path.
7. Protect your numbers: document every number to port and do not cancel the old service prematurely.
8. Schedule and test: avoid a critical trading period. Test inbound and outbound calls, alarms, payments and every connected device before sign-off.
9. Update your records: record new support numbers, contracts, equipment, passwords and renewal dates.

Questions to ask before agreeing a replacement

• Which existing services will this order replace, and which will remain?
• Can all our numbers be retained, and who manages the port?
• What installation work and new equipment are included?
• What happens to calls if the broadband or power fails?
• Are call diversion, mobile apps, support and equipment charged separately?
• What are the minimum term, notice period, price-review clauses and exit costs?
• Who will test third-party equipment, and what happens if it fails?
• When will the old service cease, and how will that date be confirmed?

Do not let the deadline force a rushed decision

The switch-off creates a genuine need to act, but it does not make every proposed replacement suitable. A very small firm with one number has different needs from a hotel, care provider, workshop or multi-site retailer. Review how calls and connected devices are actually used, then compare the complete solution, support arrangements and contract.

Starting early gives you time to investigate hidden lines, coordinate suppliers and test the migration while the existing service is still available.