Not upgraded. Switched off. By January 2027, the old analogue network goes for good. If your business hasn’t prepared, you might not find out until something stops working.

What is the Big Switch Off?

The UK has run on the same copper phone network for decades. BT/Openreach is permanently retiring it, along with ISDN, and replacing everything with internet-based systems instead.

That means landlines go digital, calls run through broadband, and fibre infrastructure gradually replaces the copper underneath. You’ll hear it described using terms like VoIP, Hosted Voice, All IP, FTTP and Digital Voice. They all sit within the same transition.

It’s not just your phone

This is where a lot of businesses get caught out. Plenty of everyday systems still rely on the old analogue lines running quietly in the background:

• Payment terminals and EPOS systems
• Alarm and security systems
• Lift lines and entry systems
• Fax machines and emergency lines
• Older broadband setups

If those systems haven’t been updated before the switch-off, they may simply stop working. The risk is that many businesses won’t discover the issue until it’s already causing disruption.

Why moving early matters

The transition has already started. Openreach has introduced stop-sell measures in many areas, meaning certain legacy products can no longer be purchased or renewed.
Leaving it too late tends to create installation delays, rushed decisions, unexpected costs, downtime and compatibility issues with older kit. Businesses that plan ahead have more flexibility, more choice and more time to get it right.

This is bigger than swapping a phone system

The businesses that have already made the move often end up in a better position than before. Cloud-based voice systems can mean calls on mobile, voicemail straight to your inbox and call routing that actually works. Systems scale without needing an engineer on-site, and for many SMEs it ends up simplifying operations and reducing costs over time.

Fibre matters too

Many businesses still run on FTTC broadband, where fibre only goes as far as the street cabinet and the last stretch into your building is still copper. The long-term direction is FTTP: fibre running directly into the premises, which means faster speeds, better reliability and stronger capacity for cloud tools and VoIP.
As more of how you run a business moves online, a solid connection stops being a nice-to-have.

The businesses most at risk

Ironically, the businesses most likely to be caught out are the ones too busy to notice. A hospitality venue whose card machine stops working mid-service. A retailer whose alarm system goes offline. A trades business that loses the landline number it has had for fifteen years. These aren’t edge cases. They’re exactly the kind of disruption that happens when infrastructure changes and nobody flagged it in time. Usually the culprit is older kit that nobody realised was still running on analogue.

What to do now

You don’t need to have all the answers today, but knowing where you stand is a good place to start. That means understanding:

• Which systems currently rely on PSTN or ISDN
• Whether your broadband is future-ready
• Whether your phone setup is already digital
• What migration timeline makes sense for your business

By 2027, this won’t be optional. The businesses that prepare early are likely to have a much smoother time of it.

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Glossary of Key Terms

PSTN (Public Switched Telephone Network): The UK’s traditional analogue phone network built on copper lines. This is the network being permanently switched off by January 2027.

ISDN (Integrated Services Digital Network): An older digital phone system commonly used by businesses for voice and internet services before modern broadband and cloud communications.

All IP: The UK’s move towards fully internet-based communication systems, where calls, broadband, and connected services run through internet protocol (IP) rather than traditional phone lines.

VoIP (Voice over Internet Protocol): Technology that allows phone calls to be made over an internet connection instead of copper phone lines.

Hosted Voice: A cloud-based phone system that enables businesses to make and receive calls via the internet, often with additional features like call routing, voicemail-to-email, conferencing, and mobile integration.

Digital Voice: A general term for internet-based calling services replacing traditional landline systems.

FTTC (Fibre to the Cabinet): A broadband setup where fibre runs to a street cabinet, but the final connection into the premises still uses older copper wiring.

FTTP (Fibre to the Premises): A full-fibre broadband connection where fibre-optic cables run directly into the property, providing faster and more reliable connectivity.

Fibre Broadband: High-speed internet delivered through fibre-optic cables rather than traditional copper infrastructure.

Copper Lines: Traditional telephone wiring used across the UK for landlines and older broadband services. These are gradually being phased out.

Openreach: The UK company responsible for maintaining much of the country’s broadband and phone network infrastructure.

Cloud Communications: Business communication systems hosted online rather than through physical on-site phone infrastructure.

Auto Attendant: An automated phone menu system that directs callers to the correct department or person.

Call Routing: A feature that automatically sends incoming calls to the right user, team, or device based on rules or availability.

Voicemail-to-Email: A feature that sends voicemail recordings directly to an email inbox for easier access and management.

Microsoft Teams Integration: The ability for phone systems and communication tools to connect directly with Microsoft Teams for calling and collaboration.

EPOS (Electronic Point of Sale): Systems used by businesses to process card payments, tills, and transaction management — some older systems may rely on PSTN connectivity.

Stop-Sell: A phase in the PSTN transition where certain older telecoms products and services can no longer be newly purchased or renewed.

Connectivity: A broad term covering internet, broadband, networking, and communication infrastructure that keeps businesses connected digitally.