Office Phone Systems for UK Businesses

If you're looking for an office phone system for your business, the choice of systems can be a bit daunting. There's no shortage of options to choose from and with plenty of technical jargon chucked into the mix, you'd be forgiven for seeking help. In this post, we review the best office phone systems currently available and explain some things to look out for when comparing them. If you need assistance in choosing the best business phone system, please request a comparison quote, and our experts will show you which is the right for your business.

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In recent years, there's been a seismic shift in how business phone systems work, which affects both small businesses and large. The introduction of VoIP, which is phone calls made over the internet, has completely changed the way businesses communicate.

Gone are the days of needing expensive physical telephone lines and digital telephone systems. With VoIP, everything is done over the internet.

As we'll explain, there are many benefits associated with VoIP, but perhaps most importantly, it's far cheaper than older technologies. For a low-cost monthly subscription, your business can now get all the office phone system features big companies have been using for years.

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Man smiling using VoIP based office phone system

Benefits of a VoIP office phone system

Far from just giving your business a reduction in costs, a VoIP office phone system will open up all kinds of possibilities for your company's communications. This section summarises some of the key benefits you can expect from VoIP phone systems.

1. Work from anywhere

Implementing a VoIP-based office phone system gives you and your team the freedom to work from anywhere, as long as you have a stable internet connection. Firstly, you can plug your desk phone into any internet connection to make calls, so if you suddenly need to have your entire workforce work from home, you can. Not only that, but you can also make and receive phone calls on your desktop computer and mobile devices. This functionality is helpful in any business where people spend time away from the office. You could be attending a conference in London when a call comes on your desk phone, and it'll simultaneously ring your mobile. From the caller's perspective, you're in the office, they've rung a landline number after all, but little do they know, with your VoIP phone system, your not.

2. Extensive functionality

If you're used to having a small business phone system that relies on ISDN telephone lines or PSTN, you likely won't be used to having a significant number of features.

Let us draw your attention to some of the best you can expect from VoIP based office phone systems.

  • Intelligent call routing and call forwarding - the latest VoIP phone systems let you tune the flow of calls to your precise requirements. You can have a virtual receptionist (auto-attendant) that distributes calls to the right people or a group of people (hunt group). You can set up rules based on the time of day and day of the week, and if you have a call centre, you can do all manner of call routing to ensure your agents never miss a beat.
  • Voicemail-to-email - this feature is a real time saver for many businesses. It means you get the convenience of picking up your voicemails just like you would any other message. Some of the best office phone systems also have voicemail transcription, so you needn't even listen back to your messages - you can just quickly read them.
  • Music-on-hold - far from being a nice to have, unimportant feature, music-on-hold isn't just for music! You can load any prerecorded message into your business phone system, and it'll be played to people while they wait. Perhaps you're running an event that you want to promote or have specific procedures or policies you want callers to be aware of. With Music-on-hold, you can communicate with your customers while they wait.
  • Call recording - there are several benefits of recording your calls, from compliance to staff training. But perhaps most importantly, by recording your calls (and telling people), you minimise the risk of disputes and have an easy way to refer back to exactly what was said between your team and customers.
  • Video calling and conferencing - the leading office phone systems include video calling and conferencing, so you and your team can do everything through a single platform.
  • And much more - there are too many features to get into in this post, but needless to say, your new VoIP based office phone system will do everything you need and more.

3. Future-proof and scalable

As we've already outlined, you'll save money by using an office phone system that runs on VoIP, plus you'll get tons of additional benefits. In addition to those, you'll also get the safety of knowing that you've future-proofed your business and have in place the latest technology.

You may or may not be aware that in 2025 BT will be turning off its ISDN and PSTN telephone networks, which means everyone, be that consumers or businesses, will need to switch to VoIP.

The other thing to add to this benefit is that VoIP phone systems are incredibly scalable, so it's doubtful you'll outgrow the system you choose. You could be a small business now with only a few handsets and then experience colossal success and grow to thousands and still keep the same VoIP system.

4. Improved call quality

So long as you have a stable internet connection and good VoIP phones, you'll experience high-definition calls with no crackling, fuzziness or distortion. At T2k, we typically recommend that you have a separate internet connection for your VoIP phones in your office to avoid your general web browsing affecting call quality. You don't have to do this, but you can ensure the best performance from your phone system for the relatively small additional investment.

The VoIP phone system has saved us serious expenditure and has changed the way we work for the better.
Steve Knell - Altogether Care
on Google
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The best office phone systems in the UK

At T2k, we regularly review all of the leading phone systems on the market to be best informed when speaking to customers. We're vendor agnostic, meaning we don't prefer one over another; we always recommend the best one for the business we're talking to.

With so many office phone systems to choose from, it's always wise to request a comparison quote from us. We will do the leg work for you and come back to you with summarised recommendations based on your requirements.

In this part of our guide, we will distinguish between telephone systems that are best for small vs larger businesses. As you'll note, some systems appear in both lists as they're suitable for companies of all sizes.

The 4 best office phone systems for small business

Currently, we recommend these five small business phone systems, each with its use-cases and applications.

If you're here looking for a business telephone system and need some assistance choosing the best for you, please request a comparison quote, and one of our experts will be in touch.

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Top-rated phone system
Gamma Horizon
Gamma Horizon

Best for: Most Small Businesses

Gamma Horizon is a cloud-based telephone system, meaning that the only equipment you have in your office is desk phones. All call processing takes place remotely, and you're subscribing to a service rather than buying anything. The great thing with Gamma Horizon is that it's been continually invested in and today represents one of the best office phone systems for small businesses.


  • Extremely competitive pricing
  • Extensive call forwarding and management options
  • Call recording and voicemail-to-email
  • Multi-level auto-attendant (virtual receptionist)
  • Compatible with market-leading VoIP phones
  • Integration with popular business software and CRMs
  • Work from anywhere with their mobile phone app
  • Take calls on your desktop with the soft client
  • Close to unlimited phone lines
  • Easy to set up and excellent support (from Gamma partner)
  • Arguably the best office phone system for small business
  • No need to have a PBX (private branch exchange) in your office


- Not as flexible as other office phone systems
- Limited handset choice
- Potentially overkill for tiny businesses


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Most flexible

Best for: Growing Businesses

3CX is different from some of the other VoIP phone systems we recommend as it isn't a fully-managed cloud-based system. Instead, with 3CX, you purchase licenses and then can choose where it is installed. However, it's not a physical phone system; it's a software-based one. It can be installed almost anywhere and likely on the equipment you already have. With 3CX, you can host the phone system in your office, the cloud or even your home if you want to. 3CX is the most flexible phone system on this list of best business phone systems and is often the least expensive. The only downside with 3CX is that it isn't as easy as others to get set up and generally requires a telecom expert's assistance.


  • Very comparatively priced - often the cheapest option for small businesses
  • Can be located anywhere, in the cloud or your office
  • No extension based pricing - everything is license based
  • Excellent mobile phone app and desktop soft client
  • Works with any IP handset - no restrictions
  • Extremely scalable
  • Extensive features for small business
  • Integrates with Microsoft Teams and Outlook
  • Integrations with popular CRMs
  • Free live chat for your website
  • Highly rated and reviewed
  • Excellent support from 3CX partners


- Not as simple as others to set up
- Requires separate rental of SIP trunks
- You have more responsibility for the phone system

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Landline Replacement

Best for: up to 3 lines

Phoneline+ is a small business phone system aimed at companies with less than three users. We're talking primarily about retailers or sole traders that need a landline replacement service. The best thing about Phoneline+ is that is it so simple to set up and use, making it extremely attractive for those who don't need all the bells and whistles of some of the other systems we've outlined. Phoneline+ gives small businesses an easy transition to VoIP, and for companies that know they won't need more than a few handsets is perfect. The only significant downside of Phoneline+ is the lack of scalability, meaning if you do grow and need more phones, you'll need to switch to a new office phone system.


  • The perfect replacement to analogue telephone lines
  • Work from anywhere with an excellent mobile app
  • Have multiple phone numbers and choose which to show when making calls
  • Voicemail-to-email
  • Low-cost and low-hassle solution aimed at smaller businesses
  • An ideal entry-level small business phone system


- Not a scalable business phone system - you can only have a few phone lines
- Limited features and functionality
- Designed for only very small business use

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beOnline beOnline

bOnline is an award-winning VoIP provider that focuses on phone systems for smaller businesses. Aimed at start-ups, freelancers and small businesses, their cloud-based system does most of what a growing company might need. They've built an excellent reputation for providing a small business phone system that doesn't overcomplicate things but is still extremely powerful. That's all backed up with UK-based support, which is excellent based on their customer reviews.


  • Unlimited UK calls
  • Excellent mobile and desktop apps
  • Voicemail-to-email
  • HD call quality
  • Easy-to-manage
  • Includes a range of call flow and forwarding options
  • One of the highest-rated VoIP providers based on customer reviews
  • Friendly UK based support


- Less handset choice
- Not as flexible as other office phone systems

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Ok, that's our rundown of the best business phone systems for small businesses; we hope it helps you in your decision-making process. Given their importance when it comes to your business phones, it's vital that you spend a bit of time reviewing the best phone systems to find the right one for your company. As we say, if you need help deciding, please get in touch.

Best office phone systems for larger businesses

As we mentioned before, some of those we recommended to small businesses are just as suitable and beneficial to larger firms, albeit with differing benefits. If you are a large company looking for a new business phone system, please get in touch to discuss your requirements; our team of experts can quickly help you identify the best solution for your business.

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Best Price & Features

Best for: Most Large Businesses

While we believe that Gamma Horizon is the best choice of cloud-based systems for small businesses, we think it's 3CX that's leading the pack when it comes to larger companies. It's pretty much unrivalled, and it's for that reason that many companies are opting for this PBX phone system over others in the market. We say this because, with 3CX, you get so many features and benefits at such a low cost. For larger companies with presences across multiple sites, you can have numerous 3CX instances, meaning there's almost no limit on the number of users it can support. Not only that, but the call management functionality is second-to-none, and you and your team will enjoy a significant improvement in your business communications. The only downside is that you'll need your SIP trunks to run a 3CX phone system, but they are quickly produced. Finally, there is tons of built-in functionality for those running call centres that'll improve efficiency and performance.


  • Excellent pricing - almost unbeatable
  • Tremendously flexible phone system
  • Take your business phone number anywhere
  • Livechat for your website
  • A true Unified Communications platform
  • Choose where it's hosted
  • Includes excellent video calling and conferencing
  • SMS functionality inbuilt
  • Internal team messaging as standard
  • Lots of call management functionality
  • Call centre specific features and functionality
  • Virtual receptionist and IVR
  • Plus, many more advanced features
  • Arguably the best office phone system


- Requires more management than other office phone systems
- You need to procure SIP (session initiation protocol) trunks

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Fully Managed Service
Gamma Horizon
Gamma Horizon

Best for: Businesses looking for a fully managed service

Gamma Horizon is just as good for larger businesses as smaller ones. However, 3CX will always come out on top from a cost perspective. That doesn't mean you should discount this business phone system, but you should be aware that it will likely cost more in the long run. The attractiveness of Gamma Horizon as a business phone system to companies of all sizes is that as far as a VoIP system goes, it does almost everything. If you're looking for reliability from your phone system (which you should be), Gamma Horizon is a top choice. It's a mature platform built on an entirely UK based network, and with hundreds of thousands of users, it's tried and tested too. If you're looking for an easy option and are happy to pay a bit more on your business phone system, then Gamma Horizon could be the best option for your business.


  • Quick and easy setup - fully managed cloud-based VoIP system
  • All phone calls are IP (internet protocol) based
  • Award-winning VoIP phone system
  • Scalable solution
  • Extremely reliable with excellent SLAs
  • Empower your team to work from anywhere
  • A Unified Communications platform
  • Easy to manage and maintain
  • Simple to transfer existing telephone numbers to
  • Highly rated by existing customers
  • Tried and tested business-class phone system
  • Lots of advanced features aimed at large businesses
  • Excellent desktop softphone
  • Hosted cloud-based solution
  • Excellent phone service for businesses of all sizes


- More expensive in the long run compared to 3CX
- Less choice over office phones
- Additional features can be costly


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Global Unified Communications

Best for: Global Companies

RingCentral is a global Unified Communications provider with a powerful proposition for larger companies looking at a new phone system. They are right up there with the best office phone systems in terms of features and functionality. However, their biggest downfall is the levels of customer service they provide. We're here to rate phone systems, not providers, and RingCentral's phone system is undoubtedly among the best currently available.


  • Designed for big business with an international presence
  • Extensive features with everything from call transfer to call recording
  • Includes video conferencing and integrates with business tools
  • Internal team chat
  • Hosted phone systems located around the world
  • Highly rated VoIP phone system


- It can be expensive to access all the features
- Customer support isn't the best

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We hope that this article goes some way to help you in finding the best office phone system for your business. As we've said a few times, the right phone system for your business will likely be different from the next, so please request a comparison quote to find out which fits your requirements.

About T2k

T2k is an independent business telecoms specialist based in Bournemouth. Having provided services to businesses for over 25 years, T2k has established itself as the go-to adviser for companies across the UK in various sectors. We take pride in our approach and treat people as we like to be treated, meaning there's never any pressure selling; we always put you and your company first.

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Lee Clarke
Sales Director

Having worked for T2k for nearly 25 years, it's fair to say that Lee is an expert when it comes to all things telephony and business communications. Overseeing the commercial side of the business, he has helped the company evolve and grow through the decades. In recent years, and with the advent of VoIP and hosted telephony, Lee has made sure that T2k is at the forefront of technological developments. With a firm interest in helping businesses navigate the world of telecoms, Lee is responsible for the majority of the content on this website.

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