What Happens If You Don't Migrate Before the PSTN Switch-Off?

If your business is still using a PSTN or ISDN line when it's switched off, it simply stops working — no grace period, no automatic fallback, and no compensation for the disruption. Openreach has confirmed the national deadline of 31 January 2027 won't be delayed again, having already pushed it back once from an earlier 2025 date. Anything still connected to the old copper network on that day, or on whatever earlier date your own provider sets, goes silent.

What Literally Stops Working on Switch-Off Day?

Every service still running over a traditional analogue or ISDN line stops functioning, which for most businesses means more than just the obvious phone line:

• Analogue phone lines and any handsets plugged directly into them
• ISDN2 and ISDN30 circuits behind older PBX phone systems
• Alarm systems and door entry systems using a phone line to communicate
• Card payment terminals connected via a phone line rather than broadband or mobile data
• Fax machines, where these are still in use
• Lift emergency phone lines, common in multi-storey buildings

It's this second group — alarms, card machines, lift lines — that catches businesses out most often, since they're rarely front of mind when people think about "switching phone providers."

Is There Any Grace Period or Soft Landing?

No. Openreach's messaging on this has been consistent and increasingly direct: the switch-off is a hard cutover, not a gradual fade. Once a line is withdrawn, it's withdrawn. There's no temporary continuation, no automatic fallback to a different network, and no compensation scheme for businesses caught out by the deadline. The responsibility to migrate sits with the business and its provider, not with Openreach.

What Are the Practical Risks for a Business?

Losing a phone line unexpectedly is disruptive on its own, but the knock-on risks are often bigger than they first appear:

• Lost calls and enquiries — no incoming line means missed business, with no warning to callers that anything's wrong
• Card payments failing — if your terminal relies on a phone line, transactions simply won't process
• Security systems going offline — an alarm system that can't communicate with its monitoring centre may not be doing its job at all
• Compliance exposure — for businesses with regulatory obligations around communication or monitoring, an unplanned outage can create problems well beyond the phone system itself

None of this is hypothetical. Openreach itself has flagged that hundreds of thousands of UK business premises were still running on legacy copper lines as the deadline approached, which gives a sense of how many businesses are genuinely exposed to this risk.

Could It Happen to You Sooner Than January 2027?

Possibly. The 31 January 2027 date is the absolute final deadline set by Openreach, but individual communications providers are free to set their own earlier cut-off dates for their own customers, and some have done exactly that. It's entirely possible your specific line could be withdrawn well before the national date, depending on your provider's own migration schedule. Checking your actual contract and provider communications matters more than relying on the national date alone.

What Should You Do If You Haven't Migrated Yet?

• Find out exactly what's still on legacy lines at your premises — use our PSTN switch-off checker if you're not certain
• Check your specific provider's own deadline, not just the national one
• Start the migration now, rather than waiting for a deadline that, by definition, leaves no room for delay once it arrives
• Follow a structured plan — our 90-day countdown checklist covers exactly what to do and when

The businesses who struggle most with this migration are consistently the ones who started latest, not the ones with the most complicated setups.

Frequently Asked Questions

Will Openreach extend the deadline again? Openreach has stated publicly and repeatedly that the 31 January 2027 date is final and won't be pushed back further, unlike the earlier 2025 date, which was delayed to give vulnerable users more time to adapt.

Is there any compensation if my business loses service because I didn't migrate in time? No formal compensation scheme applies. Responsibility for migrating before the deadline sits with the business and its provider.

What if I migrate everything except one overlooked device, like an alarm system? Only that specific device stops working — everything else on your new system continues as normal. This is exactly why a full audit of everything connected to the old lines matters, not just the obvious phones.

Can I still order a new PSTN or ISDN line before the switch-off? No. New orders for these services stopped some time ago under what's known as the "stop sell," meaning any business without a digital alternative already in place has no option to simply order more time on the old network.

The safest position is to assume your deadline is sooner than you think, and act accordingly. Request a quote for a straightforward migration plan, or follow our 90-day countdown checklist to get started.