5 Reasons to Switch to VoIP | Business Phone System Guide

By the AMVIA Team| 6 min read · Mar 2026

For UK businesses still running traditional phone lines, switching to VoIP usually comes up for a reason: rising line rental, an office move, a PBX reaching end of life, or a letter from the network about the PSTN switch-off. The five points below are the ones that come up every time an MD or IT director reviews their telephony with our team. If you want the full picture first, our business VoIP pillar covers how hosted telephony works end to end.

1. Why does switching to VoIP cut costs so sharply?

VoIP removes the line rental, channel charges, and per-minute tariffs that legacy PSTN and ISDN systems carry. A typical 10-user business on ISDN with an on-premise PBX might spend £500–£1,000 per month (typical UK 2026 range) on telephony. A comparable hosted VoIP system runs at a fraction of that — a saving of 60–80% in most of the reviews we run.

The maths holds for smaller teams too. Hosted plans start from £5.95 per user per month, which undercuts the cost of individual PSTN lines in almost every scenario we price up. The savings are not a one-off — they recur every month, and they grow as call volumes rise.

2. How does VoIP support remote and hybrid teams?

VoIP carries calls over the internet rather than a fixed line, so an extension follows the person, not the desk. Each user reaches their number through a mobile app or desktop softphone from any location with broadband. Customers dial the same business number and the call lands with the right person wherever they are working.

Hybrid and remote working are now permanent fixtures for most UK SMEs. For multi-site businesses, VoIP unifies every location under one multi-site phone system: internal calls between offices are free, and the organisation presents as a single entity regardless of geography. No more diverting office phones to personal mobiles or losing calls when someone works from home.

3. What professional features come built into VoIP?

Features that once needed an enterprise PBX — interactive voice response (IVR) menus, call queuing, call recording, and real-time analytics — are included in the monthly VoIP subscription. A three-person business can offer callers a professional IVR menu, record conversations for compliance, and review call data, with no capital outlay.

That changes how small teams compete. You sound like a larger operation without buying like one:

• IVR menus route callers to the right department on the first try.
• Call recording supports compliance and quality monitoring.
• Call queuing keeps customers in order at busy times instead of hitting voicemail.
• Analytics show call volumes, answer rates, and missed-call patterns.
• CRM integration logs calls against customer records automatically.

If telephony connects to Microsoft 365, Microsoft Teams Calling brings these capabilities into the same app your team already uses for chat and meetings.

4. Why is the PSTN switch-off forcing the decision?

The UK copper telephone network is being withdrawn, so every business on PSTN or ISDN must move to internet-based telephony. Openreach is retiring the legacy network as part of the national migration to all-IP services (Openreach). The only real question is whether you migrate on your terms or theirs.

Migrate proactively and you choose the timing, the provider, and the contract terms while you are under no pressure. Leave it late and you risk a compressed switch managed around the network's deadline, often on worse terms. Ofcom has set out how providers must protect customers — including vulnerable users — through the analogue-to-digital transition (Ofcom).

The switch-off also affects the lines people forget: fax machines, alarm panels, lift phones, and door entry systems. A proper migration review surfaces these dependencies before they fail. Around 2.4 million UK businesses still operate on PSTN or ISDN lines — the majority being SMEs; approximately 33% of large corporations still rely on analogue for some communications *(Aircall)*.

5. How well does VoIP scale as the business grows?

A traditional PBX is sized at the moment you buy it — adding capacity means capital spend and engineer time. A hosted VoIP system scales elastically: adding or removing users through an online portal takes minutes with no hardware changes. That suits any business that is growing, restructuring, or runs seasonal staffing swings.

The same flexibility applies to capability. Contact-centre features, advanced analytics, and CRM integrations can be switched on as the business matures, without changing platform or buying new equipment. You pay for what you use, when you use it.

What is the practical path to switching?

For most UK businesses the steps are: audit existing lines and dependencies, assess connectivity (broadband or a leased line), select a provider, port existing numbers, and provision handsets or apps. AMVIA manages this end to end, keeping your current communications live throughout the migration — and because we are a security partner first, your call platform is configured to be secure from day one, not patched up afterwards.