PSTN switch-off 2027: the phone line you forgot about is about to go quiet
25 businesses. One building. Nobody had a clue.
We'll be honest with you: we'd stopped talking about this.
The PSTN switch-off, the retirement of the UK's old analogue phone network, has been coming for years. It's been in the trade press, on industry panels, in every telecoms newsletter going. So we assumed that, by now, every business had heard the news and sorted it.
Then last week our MD popped into a business centre for a chat.
Every business in the building was still running on analogue lines. Every single one. And not one of them knew the network was being switched off.
That's 25 companies who, on 1st February 2027, would have picked up the phone to silence. Possibly their card machines, alarms and lift line too.
This left us with an uncomfortable question. If a whole building didn't know, how many others are in exactly the same spot?
So, if you take one thing from this blog: the switch-off is happening on 31st January 2027. That's about 14 weeks away. Here's what that means for you, in plain English.
What is the PSTN switch-off?
The old copper phone network, the one that's carried calls into British offices since Victorian times, is being retired. Its official name is the PSTN (Public Switched Telephone Network). ISDN lines, the older digital lines lots of offices used for their phone systems, are going at the same time.
Everything moves to internet-based calling instead. Same idea, different pipes.
A few things worth knowing:
The date is fixed. It was meant to be December 2025, then pushed back to 31 January 2027. In July, Openreach said plainly there would be no further extension.
You can't buy a new analogue line. Sales stopped back in September 2023.
Lots of businesses are still on it. As of September, Openreach estimated around 1.2 million lines were still on the old network, including about 350,000 business premises.
Staying put is getting pricier. Openreach has been putting up wholesale prices for old-style lines all year, and most providers pass that on.
"Won't they just move me over automatically?"
Not really, and this is the bit that catches people out. Openreach has a last-resort safety net called EVAc for some lines that haven't moved by the deadline. But by its own description it is temporary, limited and more expensive than a proper digital service. It can't be booked in advance, capacity isn't guaranteed, and lines that can't go onto it will be ceased in stages.
In other words: it's a parachute, not a plan. And it's built to keep a basic phone line alive, not your alarm panel, lift line or card machine.
Why so many businesses don't know about the switch-off
It's not because people aren't paying attention. It's because of how this stuff works in real life.
"Our phones are fine." They are, right up until the day they aren't. Nothing breaks early to warn you.
The phone line isn't in your name. In serviced offices and shared buildings, the landlord, building manager or a past tenant often set it up. Everyone assumes someone else is dealing with it.
You've heard it so often it's become background noise. The date moved once, so lots of people quietly assumed it would move again. It won't.
The scary stuff isn't just the phone. It's the alarm, the lift, the door entry and the card machine that were installed once, years ago, and never thought about since. Nobody connects those to a phone line.
The letters look like sales mail. Plenty of migration notices end up in the recycling with the energy offers.
That's exactly what happened in that business centre. Twenty-five capable, busy businesses. All of them reasonably assumed someone, somewhere, had it covered.
What's affected by the PSTN switch-off? (It's not just your phones)
Here's the thing nobody tells you. Your phones are the easy part, because if they stop, you notice in about four seconds.
The real risk is everything else that quietly uses the line to dial out. Many of these will look like they're working perfectly while failing to send anything at all.
What | What it uses the line for | What could go wrong |
Desk phones and older phone systems | Every call in and out | Silence. Customers can't reach you |
ISDN phone systems | Multi-line calling for bigger offices | The whole system goes dark, and ISDN won't be moved across for you |
Intruder and fire alarms | Signalling the monitoring centre | The siren goes off locally, but nobody's told. Your insurer may have something to say |
Lift emergency phones | Calling for help if someone's trapped | A safety-critical line that just doesn't connect. Openreach counted over 12,000 still to move earlier this year |
Door entry and intercoms | Calling a phone to let visitors in | Visitors stuck outside, deliveries missed |
Card machines (PDQ) and some tills | Processing payments, or as a backup line | Payments fail at the till |
CCTV and remote monitoring | Sending alerts and remote access | Cameras record, but alerts never arrive |
Fax machines and franking machines | Sending faxes, topping up postage | They simply stop |
Building management and telemetry | Heating, boilers, meters, gates, pumps, sensors reporting in | Faults go unreported until someone notices the cold |
Older broadband (ADSL and some fibre-to-the-cabinet) | Shares the same copper phone line | Your internet could be affected too, not just voice |
Telecare and personal alarms | Elderly or vulnerable people calling for help | Relevant for care homes, supported housing and anyone with family who uses one |
A quick note on power cuts. Old copper phones drew their own power from the exchange, so they kept working in a blackout. Digital lines run through your router, which needs mains power. Ofcom requires providers to offer people who depend on their landline a free option that lets them reach the emergency services for at least an hour during a power cut. For a business, it's worth thinking about battery backup for anything safety-critical.
Is my business affected? A two-minute check
Grab a cuppa and run through these. If you tick even one, it's worth a conversation.
Your phones plug into a socket in the wall, not into your internet router or computer network
Your phone bill mentions "line rental", "WLR", "PSTN" or "ISDN"
Your broadband is described as ADSL, or "fibre broadband" that came bundled with a phone line
You have a monitored alarm, but you've never asked how it talks to the monitoring centre
Your building has a lift, a door entry panel or a gate that "calls" someone
Your card machine plugs into a phone socket
You're in a shared or serviced building and you don't know who set up the phone lines
You can't remember the last time anyone looked at any of the above
Not sure about some of them? That's completely normal. Most people aren't, and that's exactly why we'd rather you asked.
How to prepare for the PSTN switch-off (and why January is too late)
The good news: this is very fixable. The bad news: it takes a bit longer than people think.
Find everything that uses a line. Walk the building. Check the comms cupboard, the alarm panel, the lift, the till and the back office. Make a list.
Work out who owns each line. You, your landlord, the alarm company, the lift maintenance firm? Each one may need its own fix.
Check your connection. Most moves need decent broadband, ideally full fibre, coming into the building. In older or shared buildings, that can mean new cabling to each room, just like in that business centre.
Talk to your equipment suppliers. Alarm, lift and card machine providers can usually swap in a digital or mobile-based unit. Some need replacing outright.
Move your phones. Switch to an internet-based phone system. You keep your numbers, and you usually gain features like taking calls on your mobile or in Teams.
Test it. Make a test call, trigger a test alarm, run a test payment. Then you can relax.
Why not wait until after Christmas? Because around 350,000 business premises are all chasing the same engineers, cabling slots and number transfers before the same date. Fibre installs and new cabling take time to arrange. Christmas eats a fortnight. The businesses who start now get the easy, calm version of this. The ones who start in late January get the stressful one.
PSTN switch-off FAQs
When is the PSTN switch-off?
31 January 2027. Openreach has confirmed there will be no further extension.
Will my phone number change?
No. You can keep your existing numbers when you move to a digital phone system.
Will my alarm stop working?
It might. If your intruder or fire alarm uses a phone line to contact a monitoring centre, it needs upgrading. Ask your alarm company, or ask us to check.
What happens to my lift emergency phone?
If it runs on an analogue line, it needs moving to a digital or mobile-based unit before the deadline. It's a safety-critical line, so it's worth checking first.
Will my broadband be affected?
Possibly. Older ADSL broadband, and some fibre broadband that came with a phone line, shares the same copper line. Full fibre isn't affected
What if I do nothing?
Some lines may be moved temporarily onto Openreach's last-resort service, which is limited and more expensive. Others will simply be switched off. Either way, alarms, card machines and lifts aren't protected.
How long does it take to switch?
A simple phone move can be quick. If you need new fibre or internal cabling, allow several weeks, so it's best to start now.
PSTN switch-off help in Surrey and London
We're Delta 365. We're independent, based in Egham and London, and we do this every day for businesses across Surrey and London: phones, broadband, fibre, cabling and IT support, all under one roof. Human led, tech powered means you speak to a real person who'll come and look, not a call centre reading a script.
Here's what we'll do:
A free switch-off check. We'll come and find every line in your building, including the sneaky ones behind the alarm panel.
A plain-English plan. What needs moving, who owns it, what it'll cost and when. No jargon, no pressure.
The whole job, joined up. Fibre, internal cabling, your new phone system and number transfer, handled by one team.
Coordination with your other suppliers. We'll liaise with your alarm, lift or card machine provider so nothing falls through the gaps.
Landlords and building managers, this one's especially for you. If you look after a multi-tenant building, one survey can sort every room at once. It's far easier, and much cheaper, than 25 separate panics in February.
If you've read this far and thought "hmm, I'm not sure about ours", that's your cue.
Call us on 020 4599 1365, email info@delta365.co.uk, or book your free switch-off check.
And if you know a business that might be in the same boat, please share this with them. That one conversation saved 25 companies a very bad Monday morning. Yours might save a few more.
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