PSTN switch-off countdown 2027: what every UK SMB must do before 31 January 2027

On 31 January 2027, BT Openreach retires the UK Public Switched Telephone Network — every analogue line, every ISDN circuit, every WLR2 wholesale product. If your phones plug into a master socket today, they stop working on that date — weeks away now, not years. Start today if you have not already.

Who is at risk

Roughly 2 million UK SMBs still run analogue lines, plus lift phones, alarm panels, EPOS terminals dialling for card auth, and fax machines in healthcare. Every one of these needs a replacement signed off before the cut-over.

The 6-month rollout calendar

Short on time? With the deadline only weeks away, run the steps below back to back rather than a month apart: audit this week, choose next week, then submit your port straight away — porting typically takes about 14 working days, and a new Silux Call number can be working the same day while you wait. Keep the old line live until the port completes.

1. Month 1 — audit. List every line, including ancillary devices. Note their DDIs and contract end-dates. Free template at our WLR2 FAQ.
2. Month 2 — choose. Hosted VoIP (Silux Call) vs SIP-trunk-plus-PBX. We cover both at VoIP vs SIP trunk.
3. Month 3 — port. Submit your porting request. Free porting on every paid plan; ports are handled by our team and typically take approximately 14 working days.
4. Month 4 — run in parallel. Keep both providers live for at least 7 days. Test every IVR branch, every hunt group, every recording flow.
5. Month 5 — switch ancillaries. Lift phones, alarm panels, fax. Replace with IP-native or wrap with an ATA + battery backup.
6. Month 6 — decommission. Cancel the BT line, keep the cancellation email, file with your accountant.

What it costs

For a 10-person UK SMB on Silux Call Pro (£18.95 a month, 10 users), expect about £227/year subscription (or about £205/year paying annually, 10% off), with free porting on paid plans. Ancillary device migration ranges £50-£400 per endpoint depending on age. Most SMBs pay back the project within 6-9 months versus their old WLR2 bill.

The biggest mistake

Leaving porting to December 2026. Openreach's order book will be saturated. Port at least 6 months before the cut-over.