The PSTN switch off is set for 31 January 2027. If your firm’s phone system or broadband still runs over the old copper network, you need a migration plan now, and you need to know which parts of that plan are IT and which parts belong to your landlord or security contractor.
Why the PSTN switch off affects more than your phone system
Most law firms treat the PSTN switch off as a phone upgrade and stop there. Openreach is retiring the whole copper network, not just voice calls, so any connection built on old copper lines is affected. That includes some broadband services still delivered over copper, such as ADSL and FTTC.
When is the PSTN switch off happening in the UK?
Openreach originally planned to retire the network by December 2025, then pushed the date to 31 January 2027 to give providers more time to migrate vulnerable customers safely. Openreach has since said this date will not move again.
More than half a million UK business lines are still on the old copper network. Many exchanges have already stopped selling new copper lines, so some areas are further along than the national deadline suggests. Costs for remaining copper services are rising as the deadline nears, so waiting means paying more for lines you could migrate now for less.
What needs checking in a law firm before the PSTN switch off?
Start by separating what your IT provider can fix from what needs a different call entirely.
Your main phone system and switchboard sit squarely in IT. If you’re still on an ISDN or analogue system, or a hosted VoIP setup that hasn’t been reviewed in a few years, that’s the first thing to migrate.
Your broadband connection matters too. If your office internet still runs over an old copper ADSL or FTTC line, that connection needs upgrading to full fibre before the switch off, or you risk losing internet access along with your phone lines.
Beyond IT, a law firm should also check anything else in the building that quietly relies on a phone line. Door entry systems, intruder alarms, lift emergency lines, and older card payment terminals sometimes dial out over PSTN. These aren’t something your IT provider will fix, since they belong to your landlord, alarm company, or lift maintenance contractor.
But if nobody checks them, they can fail without warning when the network switches off. Worth a call to whoever manages each one, so the responsibility doesn’t fall through the gap between IT and facilities.
What happens if you leave the PSTN switch off too late?
The practical risk is losing phone and internet service with no warning, right as your exchange is switched off. The financial risk is paying rising copper line charges in the meantime for a service you’ll have to replace anyway.
There’s also a coordination risk specific to law firms. If your phone system, broadband, and any facilities equipment migrate on different timelines with no one person tracking all three, something gets missed. That’s usually the alarm system or the intercom, since nobody in IT owns it and nobody in facilities knows it depends on PSTN.
How do you plan a PSTN switch off migration for a law firm?
Start with an audit of your own IT estate: phone lines, broadband circuits, and any analogue devices connected to your network, such as card machines or fax lines. Your IT provider should lead this part.
Separately, ask your landlord or facilities contact to confirm the status of door entry, alarms, and lift lines in your building. If you’re in a shared building, this may already be underway, but confirm it rather than assume it.
Once you have both lists, sequence the migration around business continuity. Move your phone system and broadband first, since those affect everyone in the firm daily. Building systems can follow on their own timeline, managed by whoever is responsible for them.
Where does Microsoft Teams fit in?
If your firm already uses Microsoft 365, moving your main phone system to Microsoft Teams Voice with Direct Routing is often the simplest way to get off PSTN. It keeps calling inside a platform your staff already use. Direct Routing still needs a telephony provider behind it to connect calls into Teams, so this is a migration to plan properly rather than a setting you switch on yourself.
How Labyrinth Technology helps
We’ve supplied and managed VoIP telephone systems for over a decade, and today that work is focused on law firms and financial services firms. We audit your phone system, broadband connections, and any network-connected devices still running over PSTN, then build a migration plan around your firm’s daily operations rather than a generic rollout schedule.
Get in touch to find out exactly what in your IT setup still depends on the old network.
Openreach’s deadline is 31 January 2027. That’s about six months away, and copper line costs are rising every month you wait.
