The UK’s old phone network is being switched off for good. Here’s what you need to know — and why the businesses moving early are ending up better off.

 

 

Let’s be honest: most businesses have seen the headlines about the PSTN switch-off and quietly added it to the “we’ll deal with it eventually” pile.

It’s understandable. There’s always something more urgent. But January 2027 isn’t as far away as it feels — and the businesses that leave this until the last minute are going to have a very stressful few months when it arrives.

The good news? If you move early, this isn’t a headache. It’s an upgrade.

This week, we’re breaking down exactly what’s changing, who it affects, what VoIP actually means in plain English, and a practical checklist to get your business sorted before the deadline.

 

 

 

What is the PSTN switch-off — and why is it happening?

 

PSTN stands for Public Switched Telephone Network. It’s the old analogue phone infrastructure that has underpinned UK landlines for decades — the copper wire network that most of us grew up with.

BT Openreach has confirmed that this network will be fully retired by January 2027. The reason is straightforward: the infrastructure is ageing, expensive to maintain, and simply not fit for the way businesses communicate today. The future is digital, and the switch-off is the industry’s way of making it official.

When it goes, any device or service that relies on the old analogue network will stop working. That includes traditional landlines, ISDN connections, some older fax machines, and certain alarm systems or door entry systems that use a phone line.

If your business still has any of these, now is the time to act.

 

 

 

Who does it actually affect?

 

The switch-off is more wide-reaching than many businesses realise. You’re likely affected if you have any of the following:

→ A traditional BT landline (even if you rarely use it) → An ISDN connection for phones or data → A physical fax machine connected to a phone line → A broadband connection delivered over an analogue line → Any alarm, lift, or access control system that dials out over a phone line

That last point is one that regularly catches businesses off guard. If your building’s fire alarm or intruder alarm system uses a traditional phone line to contact a monitoring centre, that connection will need updating — and coordinating that with your alarm provider takes time.

 

 

 

VoIP explained without the jargon

 

VoIP stands for Voice over Internet Protocol. Strip away the acronym and it simply means making phone calls over your internet connection rather than a traditional phone line.

You’ve almost certainly already used VoIP without realising it. Microsoft Teams calls, Zoom meetings, WhatsApp voice calls — all of these use VoIP technology. The difference for business phone systems is that VoIP gives you all the features of a professional phone system (call routing, hold music, extensions, voicemail to email) delivered entirely over your broadband or leased line connection.

For most businesses, the practical experience is identical to a traditional phone — you pick up, you dial, you talk. The difference is what happens behind the scenes, and the benefits that come with it.

 

 

 

What you actually gain:

 

→ Call from any device — your desk phone, laptop, or mobile, all on the same number

→ One number that works across your whole team, wherever they’re working

→ Call recording, call routing, and call analytics built in as standard

→ Voicemail delivered straight to your email inbox

→ No more paying line rental on multiple physical lines

→ Significant cost savings compared to traditional ISDN connections

 

 

 

The questions we hear most often:

 

“What happens if our internet goes down?” A fair concern, and the honest answer is that a reliable internet connection does matter more with VoIP. This is one reason why businesses making the switch often take the opportunity to upgrade their connectivity at the same time. With a quality broadband or leased line connection, outages are rare. And most VoIP systems allow calls to automatically divert to a mobile if there’s ever an issue.

“Will the call quality be as good?” On a decent internet connection, yes, often better. The days of tinny, laggy VoIP calls are largely behind us.

“Is it complicated to set up?” With the right provider handling the migration, it shouldn’t be. The complexity is on our side, not yours.

 

 

 

Your PSTN switch-off checklist

 

You don’t need to do everything at once — but you do need to start. Here’s a practical sequence:

✅ Audit your current phone setup. Write down every phone number your business uses, every physical line you pay for, and any devices (alarms, fax, door entry) that connect via a phone line. Most businesses discover lines they’d forgotten they were paying for.

✅ Check your broadband connection. VoIP works best on a reliable, fast internet connection. If your current broadband struggles at busy times or feels unreliable, this is the moment to address that alongside the phone migration — not as an afterthought.

✅ Talk to your alarm and access control providers. Don’t leave this until last. These third-party systems often take the longest to update, and your alarm provider will need lead time to migrate any monitoring connections.

✅ Choose a VoIP provider and plan your migration. A good provider will handle the number porting (keeping your existing numbers), configure the system to your needs, and manage the cutover so there’s no interruption to your calls.

✅ Train your team — briefly. Most VoIP systems are intuitive, but a short walkthrough of any new features (like calling from a laptop or checking voicemail by email) makes the transition seamless.

✅ Set your deadline well before January 2027. Don’t aim to complete this in December 2026. Provider capacity will be stretched as the deadline approaches. Businesses that move in 2025 or early 2026 will have more choice, more time, and less stress.