PSTN Switch-Off 2027: What UK Businesses Must Do Now

If your business still uses traditional phone lines, something important changed on 1 July 2026: the wholesale cost of those lines went up again. And another price rise is scheduled for October. By the time the UK’s old phone network finally switches off on 31 January 2027, businesses that have not moved will be paying roughly double what they were in 2025 – for a service that is about to disappear entirely.

This is not a distant problem. It is six months away.

What Is the PSTN and Why Is It Being Switched Off?

The PSTN stands for Public Switched Telephone Network – the traditional copper wire telephone network that has carried calls in the UK for more than a century. Many businesses also use ISDN (Integrated Services Digital Network), a digital upgrade to the same copper infrastructure that has been the backbone of office phone systems for decades.

Openreach, BT’s network arm, is retiring both systems permanently on 31 January 2027. The copper network is ageing, expensive to maintain, and simply cannot keep pace with the demands of modern businesses. The replacement is an all-IP network, where voice calls travel as data packets over your broadband connection – the same technology behind video calls and internet-based messaging you likely already use every day.

Why This Matters to Your Business Right Now

The switch-off affects far more than just your phone lines. If your business relies on any of the following over analogue connections, they will stop working on the deadline date:

• Business telephone systems connected to ISDN or PSTN lines
• Fax machines on analogue lines
• Card payment terminals (EPOS or PDQ machines) using old-style phone lines
• Security alarm systems with PSTN diallers
• Door entry and access control systems
• Lifts with emergency telephone connections

Openreach has already started making the cost of staying on legacy infrastructure uncomfortable. Wholesale line rental prices increased 20% in April 2026, then rose a further 40% on 1 July 2026. A final 40% increase is due on 1 October 2026. Taken together, that effectively doubles the cost of keeping old-style lines compared with 2025 rates – and you will have to replace them anyway.

There is also a practical problem: demand for engineers, compatible hardware, and project slots is building rapidly as the deadline approaches. Businesses that wait until November or December 2026 may find they are competing for a shrinking pool of resources, pushing timelines dangerously close to the wire.

What Replacing Your Phone System Looks Like

The most common solution for UK businesses is VoIP (Voice over Internet Protocol). Rather than sending voice calls down a copper wire, VoIP converts them into data and sends them over your existing broadband connection. For most businesses, this means:

No new physical lines. Your calls run over internet connectivity you likely already have.

More features at lower cost. VoIP systems typically include call recording, hunt groups, auto-attendants, mobile apps, and video calling as standard – features that cost extra on legacy ISDN systems. Most UK businesses see monthly call costs drop by 30 to 50% after switching.

Flexibility for a modern workforce. Staff can take their extension with them on a laptop or smartphone, making hybrid and remote working much easier to manage.

For businesses with a dedicated office phone system, the migration usually involves replacing a traditional PBX (the telephone exchange unit) with a cloud-hosted or on-premises IP system, and swapping ISDN handsets for IP handsets.

System Force IT installs and manages 3CX-based phone systems for clients across Gloucestershire and the UK. 3CX is a leading business VoIP platform that runs on your own server or in the cloud, giving you professional call-handling features and full control without the day-to-day complexity of managing it yourself.

What Else Needs to Change

Beyond the phones themselves, it is worth auditing everything connected to analogue lines before the deadline:

• Alarm systems: many older security alarm panels use a PSTN dialler to contact the monitoring centre. Your alarm company will need to provide a compatible digital alternative.
• Card machines: some point-of-sale terminals used PSTN as a fallback. Check with your payment processor that your hardware supports IP connectivity.
• Lifts: building managers should confirm that lift emergency phones are upgraded, as there are legal safety requirements around emergency communications in lifts.
• Fax: if you still use fax (many regulated industries do), ask your provider about fax-over-IP services that preserve the workflow without the analogue dependency.

If you are not sure which devices in your business connect via PSTN or ISDN lines, a quick infrastructure audit will surface it. As part of our managed IT services, we regularly help clients map their connectivity and plan migrations in the right order.

What to Do Before January 2027

The practical steps are straightforward:

1. Audit your lines. Find out how many PSTN and ISDN lines you have and what is connected to each one.
2. Check beyond the phones. Identify alarms, card terminals, lifts, and any other equipment that uses an analogue connection.
3. Get a quote for VoIP. A good provider will survey your current setup and propose a like-for-like replacement, plus advise on everything else that needs to move.
4. Plan in stages if needed. If you have multiple sites or complex systems, prioritise the most business-critical first.
5. Start soon. Hardware procurement, number porting, and engineer scheduling all take time, and lead times are growing month on month as January approaches.

Our IT consulting team can walk you through a migration plan that fits your timescales and budget, whether that means a complete system replacement now or a phased approach over the coming months.

The 31 January 2027 deadline is confirmed and will not be extended. The price of staying on legacy lines is already being felt on your monthly bills. The best time to plan your migration is now, well ahead of the rush.

If you would like help with your PSTN migration or choosing a VoIP phone system for your business, get in touch or call 01452 701355 for a no-obligation chat. You can also contact us online.