141 days left: the UK landline network closes on 31 January 2027

Today marks 141 days until the UK's traditional phone network switches off. On 31 January 2027, the Public Switched Telephone Network — the copper landline system that has run UK phones since the era of the exchange operator — closes for good, and every service that quietly depends on it has to have moved.

Why the deadline is real this time

The switch-off was first aimed at December 2025, then formally reset to 31 January 2027. What makes the 2027 date different is that Openreach stopped taking new orders for WLR and ISDN lines back in September 2023 — you can no longer buy the thing that is being switched off. Existing lines are on managed withdrawal, and engineeers are prioritising sites with dependent services.

Who gets caught out

The businesses most exposed are not the ones with desk phones — those are easy to move to VoIP. It is the quiet connections nobody labelled:

• Alarm signalling — intruder and fire panels dialling over a phone line. This is the single most-affected service category (see our PSTN switch-off guide and our TAP to SMS guide).
• Lift emergency phones, CCTV phone-line diallers, and EPOS/backup lines on ISDN2 or analogue.
• Fax and modem equipment in legal, medical and logistics settings.

The three moves to make this month

1. Run a line audit. Ask your line provider for every circuit against your sites, then label what each one feeds.
2. Move numbers, not just lines. Your number is your business identity — port it onto an IP service before the queue builds. DIDcomms's virtual number service takes UK geographic, 03, 084 and 0800 ranges and answers them over SIP, so the copper closing does not take your number with it.
3. Give alarm lines an IP route. If a panel still dials out over a modem, put its signalling on IP — see DIDcomms's OpenTAP gateway, which accepts the same TAP messages over TCP/IP.

Related: The UK PSTN switch-off explained · It's three years since ISDN orders stopped