The 2027 landline switch-off: what UK businesses need to do now

What is actually being switched off

Openreach is retiring the Public Switched Telephone Network, the copper-based system that has carried UK phone calls for a century. The final date is 31 January 2027, moved back from an earlier December 2025 target. After that, anything still running on a copper voice line stops working.

The mistake is hearing "phone lines" and thinking it only affects phones. It does not. ISDN2 and ISDN30 circuits go. ADSL and FTTC broadband delivered over an analogue line go with it, because the line underneath them is ceased. Roughly 60% of UK organisations still rely on PSTN or ISDN somewhere.

The things that catch businesses out

Nobody forgets their desk phones. What gets missed is everything else quietly plugged into a phone socket, usually installed years ago by a different contractor:

• Intruder and fire alarm signalling paths, which may be contractually required by your insurer
• Lift emergency phones, which are a legal safety requirement and are almost always on their own line
• Door entry systems and gate intercoms
• Card payment terminals still dialling out over a line
• Franking machines, and fax lines nobody has admitted to using since 2019

Each of these needs checking individually with whoever maintains it. An alarm that silently loses its signalling path still looks armed on the keypad, and you find out when you need it.

Why "we have until 2027" is the wrong reading

The deadline is the date the network is switched off nationally. The migration is phased and has been running since 2023, exchange by exchange. Your lines may well be moved months before the final date, on a notice period set by your provider rather than by you.

There is also a queue problem. Every business in the country needs the same engineers in the same window, and the last few months before a deadline of this size are not when you want to be booking work.

What good preparation looks like

Start with an audit of every line into the building and what is actually on the end of it — including the ones nobody can account for, because those are usually the alarm and the lift. Then check your broadband: if it is FTTC or ADSL, it is moving whether you plan it or not, and this is the natural moment to go to full fibre rather than a like-for-like swap.

One thing worth knowing before you switch: digital voice runs over your internet connection, so it does not work in a power cut the way a copper phone did. If your building relies on a phone line for safety, that needs a battery backup or a mobile fallback designing in. It is the single most common thing missed in a rushed migration.