In January 2027 every analogue and ISDN phone line in the UK is switched off permanently. It affects far more than desk phones: alarms, lift lines, and card terminals die too. Migration takes weeks, not days, and the queues get worse the closer the deadline gets. Audit your lines now, move early, and you will probably save money immediately.
In January 2027, BT switches off the UK’s PSTN and ISDN networks for good. Every analogue phone line, every ISDN2 and ISDN30 circuit, and every service still running over copper stops working.
Not degraded. Not slower. Off.
This has been coming for years and has already been delayed once, from the original December 2025 date. There will not be another extension. If your business still has anything connected to a traditional phone line, you now have months, not years, to move it.
What is actually being switched off
The switch-off covers far more than desk phones:
- All PSTN (analogue) phone lines, the standard lines most businesses have had for decades
- ISDN2 and ISDN30 circuits, which many older phone systems still use as trunks
- Broadband delivered over those lines (ADSL and FTTC services that piggyback on a phone line)
- Everything else plugged into an analogue socket: lift phones, fire and intruder alarm diallers, door entry systems, franking machines, and older card payment terminals
Plenty of firms moved their phones to VoIP years ago and assume they are done, while the lift phone and the alarm line in the comms cupboard are still analogue. Those lines stop working too, and nobody notices until the alarm company calls, or doesn't.
Who this affects
Every UK business that has not already migrated everything. Across Kent we see three groups:
- Businesses still on traditional lines entirely. Usually smaller firms with two or three analogue lines and a basic phone. The migration is straightforward, but they are also the group most likely to leave it too late.
- Businesses with an on-premise PBX on ISDN trunks. The phone system in the cupboard might feel modern, but if it connects to the network over ISDN, it dies with the network. These migrations take the most planning.
- Businesses already on VoIP with analogue stragglers. Phones are fine, but the alarm, lift line, or card terminal is not. These need identifying line by line.
Why “we’ll sort it next year” is already risky
A phone system migration is not a same-week job:
- Number porting alone takes 2 to 4 weeks, and that is when everything goes smoothly
- New systems need configuring, call flows need designing, staff need a little training
- Openreach exchanges are closing in waves, so some areas lose service before the national deadline
- Every telecoms provider in the country is migrating customers at once; the closer to the deadline, the longer the queues
Businesses that move early usually save money immediately. Waiting is costing most firms money, not saving it.
Line rental on legacy circuits is expensive, and modern hosted systems start from £7.90 per user per month with UK calls included.
What you are migrating to
The replacement is a cloud phone system (VoIP): calls routed over your internet connection instead of copper. Done properly, everything gets better at once:
- Your numbers come with you. Geographic (01/02), freephone (0800), and non-geographic numbers all port across.
- No new hardware required. Softphone apps run on the computers and mobiles your team already have. Desk phones are optional.
- Hybrid work stops being a bodge. Same number and extension at home, in the office, or on a mobile. No forwarding tricks.
- Enterprise features as standard: auto-attendants, call queues, recording, CRM integration, proper reporting.
For alarms, lifts, and payment terminals the fix varies: some move to IP-based equivalents, some to mobile or roaming-SIM connections. The important step is finding them all before January 2027 does.
A sensible timeline from here
- Now: audit every line and every device that touches one. This is the step businesses skip, and the one that prevents the nasty surprises.
- 3 to 4 months before you want to switch: choose the platform, agree the call flows, order the porting.
- Switch-over: run the new system in parallel, port numbers out of hours (typically overnight or over a weekend), verify, then decommission the old kit.
How WikiTech handles it
We supply and manage three platforms (Microsoft Teams Voice, 3CX, and VoiceFlex Flow, compared honestly here) and recommend based on how your business works, not on margin. The audit, porting, out-of-hours switch-over, and ongoing management are all handled by the same engineers who look after the rest of your IT. Most clients’ teams notice nothing on the day except that the phones look nicer.
If you are not certain what your lines are running on, that is normal: most business owners are not. It takes us about 15 minutes to find out for you.