By the Maincoms engineering team, Cosham, Portsmouth. Updated 17 October 2026.
In short: The UK copper phone network closes on 31 January 2027. Phone lines are only part of it: alarms, card terminals, lift phones, door entry systems and older broadband often use the same lines, and each needs moving to a digital service and testing before that date.
The UK's copper phone network, the PSTN, closes on 31 January 2027. Openreach has said there will be no further extension. By its own figures, reported in September 2026, around 350,000 business premises were still on analogue lines.
Most businesses we visit have already thought about their phone lines. The problems come from everything else that has been quietly using those lines for years.
The equipment that gets missed
When we audit a site, these are the items most often left out of the plan:
- Intruder and fire alarms. Many alarm diallers report to the monitoring centre over an analogue line. If the line stops, the alarm may still sound on site but nobody is told. Your alarm company will need to fit an IP or 4G communicator.
- Card payment terminals. Older terminals that dial out to authorise payments will stop working. Most can move to broadband, Wi-Fi or a SIM, but it needs testing before the day.
- Lift emergency phones. These are a safety requirement, so a lift without a working line may have to be taken out of service. They need a digital line or a dedicated 4G autodialler, tested with your lift maintenance company.
- Door entry, gates and barriers. Systems that dial a mobile when someone presses the buzzer often rely on a phone line.
- Broadband on an old phone line. ADSL and most FTTC broadband are delivered over a PSTN line. They move to SoGEA or full fibre, which do not need a phone line at all.
Why waiting is risky
Openreach has announced a temporary emergency voice service for some lines that have not moved by the deadline. It is limited to essential calls, costs more than a modern service and is not designed to keep an alarm or card machine working. It is a safety net, not a plan.
There is also the simple problem of capacity. Every installer, alarm company and lift engineer in the country is working to the same date. The closer it gets, the longer the lead times.
What to do this month
- Find your most recent phone bill and list every line number on it.
- Walk round the building and note anything plugged into a phone socket.
- Ask your alarm company, card terminal provider and lift maintenance company what they need from you.
- Book the migration in stages, so each device is tested on its new connection before the old line is ceased.
Our free switch-off site checklist covers every item above and has space to note each line. If you would rather we did it, we can carry out a line audit and give you a written migration plan.
Figures from Openreach, as reported by ISPreview in September 2026.
Frequently asked questions
When does the BT switch-off happen?
Openreach's analogue phone network (the PSTN) closes on 31 January 2027. Openreach has said there will be no further extension, so any service still using an analogue or ISDN line needs to move before then.
Will our business phone numbers change?
No. In most cases your existing numbers are ported to the new hosted phone system or SIP trunks, so customers keep dialling the same numbers.
Will our intruder or fire alarm stop working?
An alarm that signals over an analogue line may still sound on site but could stop reporting to the monitoring centre. Ask your alarm company to fit an IP or 4G communicator, and test it before the old line is ceased.
What is SoGEA?
SoGEA is broadband delivered without a phone line. It replaces FTTC broadband, which needs an analogue line underneath it, and is one of the main options for businesses moving off copper.