The PSTN switch-off: what hybrid-working financial firms need to do before January 2027
22 September 2026
The UK's analogue phone network is on its way out, and the deadline has finally stopped moving. After two delays, mostly over concerns for vulnerable customers on telecare devices, the final switch-off of the Public Switched Telephone Network (PSTN) is now locked in for 31 January 2027. ISDN lines, the digital-ish business standard many firms still run their main office number on, can no longer even be ordered new, the "stop sell" already took effect. If your business hasn't planned its migration yet, this is worth treating as a real deadline, not a background telecoms story.
What's actually changing
Every analogue and ISDN line in the country moves to Digital Voice, calls carried over broadband rather than copper wire. For most businesses that means hosted VoIP or a similar cloud phone system, your numbers, call routing and voicemail living online rather than in a box in a cupboard. Ofcom's own figures show the number of UK residential lines still on the old network fell from 5.2 million to 3.2 million between July 2024 and July 2025, so the migration is genuinely underway, but a recent industry survey still found nearly half of people unclear on what steps they actually need to take. Businesses aren't necessarily any further ahead.
Why this matters more once you're hybrid
A single office landline used to be a simple thing to plan around. A hybrid team, calling clients from home broadband, a mobile, a co-working space, and the office on different days, makes "just swap the phone system" a less complete answer than it sounds. The new setup needs to work the same way regardless of where someone's actually sitting, and needs to fail gracefully too, unlike the old copper network, VoIP depends on power and broadband both staying up, which a traditional analogue line didn't.
The part that's easy to miss if you're a regulated firm
If you're FCA regulated, or your firm has obligations to record certain business communications, existing taping and call recording requirements don't pause for a phone system migration. Moving to a hosted VoIP platform changes where those recordings live, how long they're retained, and who can access them, and it's worth confirming your new system meets those requirements before go-live, not after a request for a recorded call turns up nothing. This isn't purely an IT project. It's a compliance one wearing an IT hat.
What to actually do before the deadline
- Walk the building and list every device connected to a phone line, not just the handsets, alarms, card machines, door entry, lifts and fax lines all need a digital replacement too
- Confirm your broadband connection is digital-ready before committing to a cutover date
- If you're regulated, confirm the new system's call recording and retention meets your existing obligations, in writing, before switching
- Plan the cutover itself around your quietest period for client calls, not the provider's convenience
- Test what happens during a power cut or broadband outage, and have a fallback (mobile diversion, at minimum) ready
Where we come in
We help clients plan and run this migration properly, including keeping regulatory recording obligations intact through the switch, so it's a smooth upgrade rather than a scramble in December 2026.
Sources: Ofcom PSTN migration figures, House of Commons Library briefing on the switch to digital landlines, April 2026; Community Fibre digital voice readiness survey, August 2026.
