The PSTN Switch-Off: A Practical Guide for Businesses

The UK's old analogue phone network, the PSTN, is being retired. The final date is 31 January 2027, and Openreach has said there is no extension. This guide explains what is changing, what could stop working and what to do about it.

Last reviewed 8 October 2026. Details can change, so check with your provider.

What is changing

BT is retiring the PSTN, and Openreach is withdrawing its Wholesale Line Rental (WLR) products, which is what most analogue business phone lines and ISDN services run on. No new analogue lines have been available since September 2023. Voice calls move to internet-based services, such as hosted VoIP or SIP, delivered over broadband, fibre, leased lines or mobile data.

What could stop working

• Business phone lines and ISDN phone systems
• Fire and intruder alarms, and their monitoring
• Lift emergency phones
• Door entry systems
• Card machines and payment terminals
• Fax lines and other older devices
• Some older copper broadband lines that depend on the phone line

Many of these are installed and maintained by other companies, such as your alarm, lift or card machine provider, so they do not appear on your phone bill. That is why a proper inventory matters.

What about the emergency fallback?

Openreach has said a temporary Emergency Voice Access (eVAC) service will be available for lines that have not migrated, and has widened it to business lines and, where technically possible, linked broadband. It is a limited last-resort service for essential calls, with migrations onto it expected to start from February 2027 and broadband-linked lines from mid-April 2027.

I would not plan around it. It is not a replacement for a proper migration, and earlier descriptions said it would not carry critical alarm and lift signals. Details may still change.

What to do now

1. List every line. Include phone numbers, fax, alarms, lift phones, door entry, card machines and anything else plugged into a phone socket.
2. Find out who looks after each one. Ask your alarm, lift and card machine suppliers whether their equipment depends on an analogue line, and what they plan to do.
3. Check your broadband. Some older copper broadband services depend on the phone line, so ask your provider.
4. Decide how voice will work. Hosted VoIP, SIP or a system such as 3CX are the usual options. Make sure your internet connection suits voice calls.
5. Plan your numbers. In many cases you can keep your existing numbers, but moving them needs notice and coordination.
6. Book the work early. Engineer visits, new circuits and number moves all take time, and availability tightens as the deadline approaches.
7. Test before you cut over. Check calls, alarms, lifts and card machines before the old line is switched off.

Questions to ask your phone supplier

• Which of my lines and services are affected?
• What is the replacement, and what will it cost?
• Will I keep my numbers, and when will they move?
• Is my broadband suitable for voice?
• What happens to my alarms, lift phones and card machines?
• Who is responsible for each part, and by when?
• What does it cost to leave my current contract early?

How I can help

I can list what you have and find what depends on it, plan the move to a digital service, move your numbers, supply and support VoIP or 3CX, and coordinate the suppliers involved so that nothing is missed.