The Best Modern Business Phone Systems

For a deeper look at how this infrastructure change affects your connectivity more broadly, our digital switchover and business broadband guide covers what's changing at the network level.

Your Options: VoIP, Hosted PBX and Cloud Phone

The jargon used in this space can be confusing, so it's worth clarifying the three terms you'll come across most.

VoIP (Voice over Internet Protocol) is the underlying technology. Instead of routing your audio through copper telephone lines, calls travel as data packets over your broadband connection. Every modern business phone system you're likely to consider uses VoIP at its core.

Hosted PBX is a VoIP-based service where your provider manages a Private Branch Exchange (the call-routing system) in their own data centre. Your office gets the feel of a traditional phone system with extensions and call queues without the hardware sitting on-site.

Cloud phone systems are often used interchangeably with hosted PBX, but the term increasingly refers to more software-driven solutions like apps, integration with Microsoft Teams or Google Workspace, and minimal hardware. The distinction only really matters to you when you're deciding whether your team need physical handsets on their desks.

All three of these approaches run over your existing business broadband connection, which means broadband reliability is a genuine prerequisite, and something worth seriously assessing before you choose a phone system provider.

VoIP vs Traditional Landline

The case for switching goes well beyond compliance with the 2027 deadline. According to 2026 industry benchmarks, a hosted VoIP system typically costs between £5 and £25 per user per month, while a traditional ISDN line with equivalent features runs to £25-£45 or more per line.

For a 10-user team, that's a difference of £60-£150 per month versus significantly higher legacy costs, with most businesses saving between 40% and 70% on monthly phone bills after switching, according to data from Connection Technologies.

Beyond cost, the feature gap is substantial:

• Auto-attendant and call routing

• Call recording

• Mobile and desktop apps

• Video conferencing

• CRM integrations

• AI-powered features

• Instant scalability

Traditional landlines offer none of this without expensive add-ons, and the infrastructure supporting them won't exist soon anyway. For a side-by-side breakdown with more detail, our VoIP vs landline for business comparison covers the key differences in depth.

The Top UK Phone System Providers

The UK market has changed significantly in recent years. Here's how the main options stack up for SMEs.

RingCentral RingEX

Consistently rated the best all-round business VoIP platform by PCMag UK (April 2026) and Expert Market. Pricing runs from approximately £12.99 to £29.99 per user per month, with over 300 third-party integrations, a 99.999% uptime SLA, AI call summaries, and strong Microsoft Teams compatibility.

This provider is best suited to businesses with more than 10 users needing a comprehensive communications platform.

8x8 Work

Strong choice if your business makes international calls. 8x8 bundles unlimited calling to over 40 countries in its higher-tier plans, and its contact centre features are among the best in class. Pricing typically falls between £10 and £20 per user per month in the UK.

8x8 is well regarded for analytics and reporting.

Gamma Horizon

A UK-native carrier-grade hosted PBX platform, sold through reseller partners rather than direct. Gamma is widely considered a reliable choice for UK SMEs thanks to established infrastructure, strong uptime record, and pricing generally between £9.95 and £22.95 per user per month, depending on tier and reseller.

AMVIA's April 2026 comparison rates it the top choice for UK-focused SMEs wanting a managed service at a budget price point.

bOnline

The budget entry point for smaller teams. At approximately £7-£15 per user per month, bOnline is the cheapest full-featured VoIP option in the UK market, suited to businesses with under 50 users that want simplicity and reliability without advanced integrations.

bOnline won the ISPA Best Voice Provider award for 2025.

Dialpad

This provider leads on AI features like real-time transcription, sentiment analysis, and automated meeting notes, which are built in at the standard tier. Pricing is competitive in the £10-£20 range.

Dialpad is a strong fit if your team relies heavily on call intelligence.

Microsoft Teams Phone

If your business already uses Microsoft 365, Teams Phone (via a calling plan or direct routing through a UK carrier like Gamma) effectively turns Teams into your phone system. No additional app is needed, and calls can be made and received on existing devices.

This option is certainly worth exploring before committing to a standalone platform.

For a more thorough guide to assessing your options, how to choose the best VoIP service walks through the evaluation criteria in practical terms.

Provider Comparison in Summary

What to Check Before Switching

Broadband Connection

VoIP call quality is directly influenced by your internet connection. A basic rule of thumb is that you need roughly 100 Kbps of bandwidth per simultaneous call, but latency and ‘jitter’ matter more than raw speed. High latency (above 150ms) or packet loss above 1% will produce audible call quality problems regardless of the provider you choose.

If your business runs on standard FTTC broadband, most deployments handle VoIP without issue. If you're processing high call volumes or running a customer support centre, a dedicated business leased line gives you guaranteed symmetrical bandwidth and a Service Level Agreement - something standard broadband won’t.

Number Porting

You can keep your existing UK area code number (e.g. 0161 for Greater Manchester-based companies) when switching to VoIP. The porting process takes somewhere between 2 and 10 working days, depending on the complexity, and your provider manages it on your behalf.

Run the porting in parallel with your new system going live, keeping your existing line active until the port completes.

Related Devices

This is the part many businesses overlook. The following equipment may also rely on your copper telephone line and will need some attention:

• Card machines: older PSTN-connected card machines will fail

• Burglar alarms and CCTV: some will need reconfiguring or replacing

• Door and intercom systems

• Fax machines: switch to cloud document sharing

• Lift emergency phones: these are a critical item requiring action

Power Resilience

Unlike a traditional handset that draws power from the phone line itself, VoIP phones depend on your broadband router being powered. In a power cut, both go down unless you have a UPS (Uninterruptible Power Supply) or a backup device. This is worth flagging if your business handles emergency calls or has a legal obligation to maintain communications.

How to Switch: Step-by-Step

1. Audit Your Setup

List every device connected to your phone lines. Not just handsets, but alarms, card machines, fax machines, and any ISDN-connected PBX hardware.

2. Check Your Broadband

Run a speed and latency test during peak hours. If you're on an older ADSL or FTTC connection, this is a good moment to look at upgrading. The benefits of full fibre broadband are significant for businesses using cloud services.

3. Choose Your System Type

Decide whether you need desk phones (hosted PBX) or can operate entirely through apps (cloud phone system). For SMEs with under 20 employees, app-based systems are both cheaper and more practical.

4. Compare Providers

Match requirements against pricing tiers. Check whether the provider offers UK-based support, what their uptime SLA is, and whether number porting is included without extra charge.

5. Port Your Number

Don't get rid of the old line until the new system is fully tested and the port is confirmed.

6. Address Devices Separately

Coordinate with your security provider, payment provider, and any other suppliers regarding devices that currently run on your copper line.

7. Train Your Team

Most cloud systems are intuitive, but a short walkthrough of call routing, voicemail, and mobile apps prevents operational friction.

Our VoIP systems comparison is a practical starting point for mapping your requirements to the right solution.

Frequently Asked Questions

Can I keep my existing phone number with VoIP?

Yes. UK landline numbers can be ported to VoIP providers. Your number stays, and your area code stays.

Do I need new hardware to go digital?

Not necessarily. Many VoIP systems work entirely through apps on existing computers and smartphones.

If you want physical desk phones, IP handsets are available from around £40, and some providers include them in bundle pricing.

What happens if my broadband goes down while using VoIP?

Most providers offer call forwarding to a mobile number. Some include a 4G SIM-based backup option.

This is a key question to raise with any provider before you sign a contract.

Can I use VoIP with Microsoft Teams?

Yes. Teams Phone (formerly Teams Calling Plans) is already widely used by UK businesses in the Microsoft ecosystem. Carriers including Gamma offer direct routing integration.

Is the switch to a modern phone system mandatory?

Yes, in practical terms. After January 2027, PSTN and ISDN lines will cease to function.

As Openreach's own guidance makes clear, the network is already being wound down in phases. Waiting until the last minute only creates continuity risk.

PSTN Switch-Off: Key Insights

Choosing a Business Phone System Provider

The 2027 PSTN switch-off deadline removes the option to do nothing. Replacement systems available now are genuinely better than what they're replacing, with lower monthly costs, features that would have required expensive hardware a few years ago, and the flexibility to support hybrid or remote-working colleagues.

For most small businesses, a hosted VoIP or cloud phone system will be a straightforward upgrade. The critical steps are auditing what currently runs over your phone line, confirming your broadband is fit for purpose, and not leaving number porting to the last minute.

BusinessComparison makes it straightforward to compare VoIP systems and cloud phone systems side by side, so you can assess your options and find a UK provider that fits your budget and requirements without spending hours trawling through supplier websites.