What is the PSTN switch-off in 2027 — and what does it mean for my business phones?

If you have had a letter from your phone provider about the “PSTN switch-off” and quietly filed it under “deal with later”, you are in good company. Here is what it actually means, in plain English.

What is the PSTN?

The Public Switched Telephone Network is the old copper telephone network — the one that has carried UK phone calls for over a century. Openreach is retiring it, along with ISDN, and replacing it with services that run over broadband instead. Once it is gone, an analogue line simply will not work.

The deadline has moved before, and the industry is now working to a completed migration in January 2027. Salespeople will tell you that is ages away. It is not, because of what else is plugged into those lines.

It is not just your phones

This is the part most businesses miss. A surprising number of things quietly depend on an analogue line:

• Lift emergency phones
• Intruder and fire alarm signalling
• Door entry systems
• Card payment terminals
• Fax lines still connected to a scanner nobody has looked at since 2014
• Franking machines and EPOS systems

Each of these needs checking, and some need replacing. A school with a lift, a care home with an alarm panel, or a shop with an old card terminal cannot simply port the phone number across and call it done.

What replaces it?

For voice, the answer is almost always VoIP — your phone system running over your internet connection. In practice that means:

• Calls that work wherever your team is, on a desk phone, a laptop or a mobile
• Call transfer, call recording, reporting and video calling built in as standard
• Numbers that move with you if you move premises
• No physical line rental

The one thing VoIP genuinely depends on is a decent internet connection. If your broadband is already the weak link, sorting out full fibre connectivity is the first job, not the second.

How long do I actually have?

Long enough not to panic; not long enough to ignore it. The sensible sequence is:

1. Audit. Find every analogue line in the building and what it does.
2. Check the connection. Confirm your broadband can carry voice reliably.
3. Migrate the phones. Port numbers, set up the new system, train the team.
4. Deal with the awkward ones. Lifts, alarms, card machines — these take the longest and are the ones people leave to the end.

Leave it until late 2026 and you will be joining the queue with everyone else who also left it until late 2026.

What we would suggest

Book a line audit. It takes an engineer an hour or two on site, and you come away knowing exactly what is connected to what, what needs to change, and roughly what it will cost. There is more detail on our PSTN switch-off page, and if you want to see how a modern system works before committing, our VoIP and telephony page walks through the features.