5 Best Business VoIP Phone System Options for UK Companies
For UK companies evaluating VoIP options in 2025, the top five choices are Gamma Horizon, 3CX, RingCentral, Microsoft Teams Phone, and Vonage. This comparison looks at what each option delivers for different business sizes, with pricing from £8 to £25 per user per month.
Ollie Hill-Haimes
Sales Director
Five VoIP Options Worth Evaluating
Choosing a VoIP phone system involves balancing features, price, reliability, and fit with your existing technology. This guide covers five of the strongest options for UK businesses, with honest assessments of who each suits best.
Option 1: Gamma Horizon — Best for UK SMEs Wanting a Managed Service
Gamma Horizon is built on Cisco Broadworks carrier infrastructure and delivered through a network of UK resellers. It is widely regarded as one of the most reliable hosted VoIP platforms in the UK market, with strong SLAs and a comprehensive feature set.
Features include auto-attendant, hunt groups, call recording, voicemail to email, mobile and desktop apps, and detailed analytics. Microsoft Teams integration is available as an add-on, allowing Teams to be used as the calling interface on the Gamma network.
Pricing: £12–£18 per user per month. Best for businesses of 5–200 users wanting a fully managed, reliable UK-hosted system.
Option 2: 3CX — Best for Cost Efficiency and Configuration Control
3CX is a software PBX that offers hosted, cloud, or on-premise deployment. It is particularly popular with IT-managed businesses and MSPs because it provides full platform configuration access. The open architecture supports a wide range of SIP endpoints and carrier integrations.
3CX includes a full web client, mobile apps, video conferencing, call centre features, and CRM integrations with Salesforce, HubSpot, and Dynamics. It is one of the most feature-rich platforms at its price point.
Pricing: From £8–£14 per user per month (hosted). Best for businesses with IT support capability or a managed IT provider who can configure and maintain the platform.
Option 3: RingCentral — Best for Deep Integrations
RingCentral's MVP (Message, Video, Phone) platform is a mature UCaaS solution with an extensive library of third-party integrations — more than 250 apps including Salesforce, Zendesk, HubSpot, and ServiceNow. It is the strongest choice for businesses where CRM and helpdesk integration is a primary requirement.
RingCentral's analytics are detailed and its contact centre add-on is well regarded. However, its pricing places it at the upper end of the market, and smaller businesses may find the feature complexity unnecessary.
Pricing: £15–£25 per user per month. Best for businesses of 20+ users with significant integration requirements.
Option 4: Microsoft Teams Phone — Best for Microsoft 365 Users
Microsoft Teams Phone transforms Teams into a full business phone system. Adding a Teams Phone licence enables call queues, auto-attendant, call recording, voicemail, and external PSTN calling through either Microsoft's Calling Plans or a third-party direct routing provider. All calls are managed within the Teams interface staff already use daily.
The total cost of Teams Phone (licence plus calling plan) is approximately £11–£21 per user per month — comparable to or below dedicated VoIP platforms, with the advantage of being fully integrated with Microsoft 365.
Pricing: Teams Phone licence £6–£12/user/month + Calling Plan £5–£9/user/month. Best for businesses already on Microsoft 365 E3/E5 or Business Premium.
Option 5: Vonage — Best for Developer-Friendly Businesses
Vonage (now part of Ericsson) provides a hosted VoIP platform alongside a developer-focused API suite. For businesses that want to embed communications in custom applications — click-to-call in CRM, in-app voice or video, automated SMS — Vonage's API platform is well regarded. The standard hosted VoIP product is competitive on price and includes a solid feature set.
Pricing: Approximately £10–£20 per user per month. Best for businesses with development resource wanting to integrate communications into custom workflows.
Making the Decision
For most UK SMEs, the choice comes down to: managed reliability (Gamma), cost and flexibility (3CX), Microsoft integration (Teams Phone), or extensive third-party integrations (RingCentral). AMVIA can provide a no-obligation comparison based on your specific requirements, user count, and budget.
Not Sure Which VoIP Option Fits Your Business?
AMVIA provides independent VoIP advice — comparing platforms against your actual requirements and giving you an honest recommendation.
Frequently Asked Questions
For a 10-person UK business, Gamma Horizon and 3CX are both strong choices. Gamma provides a fully managed, reliable service with minimal IT overhead. 3CX offers more configuration options at a lower price point. Microsoft Teams Phone is worth considering if the business already uses Microsoft 365.
Gamma Horizon is sold exclusively through a network of UK reseller partners rather than directly to end users. Managed IT providers and telecoms resellers like AMVIA are authorised to supply and configure Gamma Horizon, providing managed setup, support, and ongoing management.
Both are UCaaS platforms with hosted VoIP, messaging, and video. RingCentral has a larger integration library and stronger enterprise features. Vonage differentiates with its API platform for developers building custom communications integrations. For standard business use, both are comparable — RingCentral is generally the stronger choice for non-developers.
Yes. Number porting allows you to transfer your existing phone numbers when switching VoIP providers. This includes all UK number types (01, 02, 03, 0800). The porting process takes approximately 5–10 working days. Your new provider coordinates the transfer.
Contract terms vary. Most providers offer 12 or 24-month contracts with discounted rates, plus rolling monthly options at higher per-user costs. Gamma Horizon and RingCentral typically require minimum 12 months. 3CX hosting can often be arranged on monthly terms. Microsoft Teams Phone licensing follows Microsoft's standard annual or monthly commitment options.
Call quality depends more on your internet connection than on the VoIP platform. All five platforms use modern codecs and quality carrier infrastructure. On a good business broadband or leased line connection, all will deliver clear, reliable call quality. Latency, jitter, and packet loss on the underlying connection are the primary determinants of audio quality.
Related Reading
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