UK Business Guide
VoIP vs Landline: which is right for your UK business?
With BT switching off the analogue PSTN network by January 2027, every UK business needs a plan to move from traditional landlines to VoIP. This guide compares the two on cost, features and reliability so you can choose with confidence.
What is a business landline?
A traditional business landline uses the Public Switched Telephone Network (PSTN) — a circuit-switched copper network that has carried UK phone calls for over a century. Each line typically requires a physical connection into your premises, line rental to Openreach, and often an on-site PBX to handle multiple extensions.
It is a proven, familiar technology, but it is also being retired. Openreach stopped selling new PSTN and ISDN lines in September 2023, and the full switch-off completes on 31 January 2027.
What is VoIP?
VoIP (Voice over Internet Protocol) converts voice into data and sends it over your existing internet connection. There is no separate phone line — calls travel over the same broadband or fibre link that powers the rest of your business.
A hosted VoIP service (like Smallworld Voice Hosting's Hosted PBX) also moves the phone system itself into the cloud, so you avoid buying, housing and maintaining PBX hardware on site.
VoIP vs Landline at a glance
| Feature | VoIP | Landline (PSTN) |
|---|---|---|
| Monthly cost | Low — from a few pounds per user | Higher — line rental + call charges |
| UK calls | Usually inclusive | Metered per minute |
| Hardware | IP phone, softphone or ATA | Analogue phone + on-site PBX |
| Scalability | Add users instantly | Engineer visit + new lines |
| Remote / mobile working | Yes — anywhere with internet | Tied to the physical line |
| Features (IVR, voicemail-to-email, call recording) | Included | Extra hardware / licences |
| Available after Jan 2027 | Yes | No — being switched off |
Lower running costs
No line rental, inclusive UK minutes and no on-site PBX to maintain typically cuts telephony spend by 40–60%.
Modern features built in
IVR menus, hunt groups, call recording, voicemail-to-email, CRM integrations and analytics — all standard on hosted VoIP.
Work from anywhere
Take your extension with you on a laptop or mobile app — ideal for hybrid teams and multi-site businesses.
Future-proof
Moving now avoids a rushed migration ahead of the January 2027 PSTN switch-off — and keeps your existing phone numbers.
When a landline might still make sense
VoIP relies on your internet connection, so if broadband in your area is poor a landline can feel more resilient — but only until the switch-off in 2027. In practice, a well-provisioned business fibre line with a 4G or 5G failover delivers better uptime than most legacy landlines, and calls automatically re-route to mobiles or other sites if the office drops offline.
How to move from landline to VoIP
- Audit your current lines, numbers and call volumes.
- Check your broadband — most fibre connections comfortably handle VoIP.
- Choose a UK VoIP provider and a Hosted PBX or SIP Trunk plan.
- Port your existing numbers so customers see no change.
- Roll out IP handsets or softphones and train your team.
Frequently asked questions
Is VoIP cheaper than a business landline in the UK?
Yes. There is no line rental, UK calls are typically inclusive, and you avoid the cost of an on-site PBX.
Can I keep my existing phone number?
Yes — UK numbers port to VoIP providers, usually within 10 working days, with no change for your customers.
What happens in a power cut?
Calls automatically re-route to mobiles or another site. Battery back-up on your router keeps handsets working during short outages.
When is the UK landline switch-off?
31 January 2027. After that, all UK voice services run over IP.