Choosing a Telephony Provider for Your Small Business: The Main UK Options

By John Rowlinson

I run a small UK business and have used several phone systems over the years. These days I run 3CX. Before I write about setting that up, this article looks at the bigger choice: which kind of telephony provider suits a small business, who the familiar names are, and what to ask before you sign anything.

Why many small firms are choosing now

Traditional analogue phone services on the public switched telephone network (PSTN) are being retired, with BT's migration scheduled to finish by 31 January 2027. This does not mean every copper broadband line is being removed. It does mean calls will run over internet connections instead.

If your business still uses an analogue telephone service or ISDN, you will need to move at some point. Doing it on your own timetable is far less stressful than doing it in a rush. Dates have shifted before, so check GOV.UK, Ofcom and your current provider for the latest position.

Common buying routes

Most options fall into four common buying routes, which overlap. UK providers also sell cloud systems, and a reseller may supply Teams calling or 3CX. The names below are examples, not recommendations.

Cloud phone system providers. These are usually sold per user per month. The provider operates the hosted phone platform, you get an app and often desk phones, and you manage users through a web portal. Well known names include RingCentral, 8x8, Vonage, Zoom Phone, Dialpad and Nfon. Many are international companies, so check how their UK support and UK numbers work.

UK-centric providers and BT. BT offers cloud telephony through BT Cloud Phone and its BT Business range. Gamma Horizon is a widely used UK platform, normally bought through a reseller, so the reseller matters as much as the platform. Smaller UK specialists include Yay.com, Circleloop, Sipgate and Soho66.

Microsoft Teams Phone. If your business already lives in Microsoft 365, Teams Phone adds calling to the Teams app. It suits staff who work mainly at laptops with headsets. You need the appropriate Teams Phone entitlement as well as connectivity to the public telephone network, and an existing Microsoft 365 subscription does not necessarily include either. Ask for an itemised licensing quote.

Your own phone system software. Products such as 3CX let you run your own system, hosted in the cloud or on your own server, with SIP trunks from a separate carrier. You get more control but take on more of the setup and responsibility. Our article Choosing a Business Phone System: Hosted, Teams or Your Own PBX compares these approaches in more detail.

For my own SIP trunks I use Telnyx. What won me over was the choice of local numbers: I could pick from a big range in my own area code for about a dollar each, and the line costs me about a dollar a month. I got memorable sequences such as 411000, 411411, 411001 and 411002 on my local 01 code without paying any premium. There is more on that in Choosing a SIP Trunk Provider and Getting Memorable Local Numbers. Prices are in US dollars and change, so check the current rates, but it shows how much cheaper and more flexible trunks can be when you run your own system.

Handsets, phonebooks and leaving

This area rarely comes up in a sales demonstration.

Over the years we have tried a few routes. We used Spitfire for our phone system before moving to something more modern, and I also used RingCentral for a while. For a business with a few telephone lines it was fine. Where it fell down for me was the handsets: they came with a locked provisioning profile, so I could not push my own company phone book to the phones. With hundreds of customer and supplier numbers, that mattered.

I had the same problem with Voipfone in the UK. I paid for a premium number there, but again the handsets were locked and there was no way of identifying who was calling: incoming calls just showed a number.

What we do now is publish the company phonebook to an internal web page, and the handsets download it every hour and update themselves. When a customer rings, their name is on the screen before anyone picks up. That only works if the provider lets you control the handsets. I explain the problem in Why Your Business Phones Don't Show Who's Calling, and how we set it up in How to Push a Company Phonebook to Yealink Desk Phones Automatically.

That was my experience at the time. Plans and features change, so check with any provider what applies today. The general point stands: hosted providers often lock handset settings, which limits what you can do. Ask whether you can:

• load a shared company phonebook onto the handsets
• use CRM caller lookup, so the caller's name appears from your customer records
• choose your own handsets, or only those the provider supplies
• get your numbers, contacts and recordings out if you leave

On that last point, separate your data from your setup. Contacts and call recordings can often be exported, but system configuration such as call flows and queues may not transfer to another platform at all. Ask what you would have to rebuild.

Your situation may be slightly different. ask a question below ↓ and our editorial team will reply with our advice.

Questions to ask before you sign

Get the answers in writing where you can.

• Contract and costs. What are the minimum term, notice period and early termination charges? Do prices include VAT? Are there setup and porting fees? Are handsets bought or rented? How do annual price rises work? Does adding users or equipment start a fresh minimum term?
• Users and calls. If pricing is per user, does a reception or meeting room phone count? What is in the call bundle and what fair use limits apply? What do calls to mobiles, non-geographic numbers and overseas numbers cost?
• Number porting. Fixed-line ports do not use the mobile PAC code: the gaining provider normally handles the request. Do not cancel your existing service before the port completes. Ask whether moving the number will cease associated broadband, what downtime to expect, and whether every number in a multi-number range can transfer. Ofcom has the current rules.
• Call recording and AI. You need a lawful basis, a way to tell callers, access controls, retention and deletion periods, and the provider's processor terms. UK GDPR does not generally require UK-only storage, but overseas processing needs appropriate transfer arrangements. Apply the same checks to AI transcripts and summaries, including whether the supplier uses them to train models. The ICO's guidance on call recording and international transfers is the place to check.
• Integrations and apps. Does it connect to Microsoft 365 and your CRM? During a trial, check the mobile and desktop apps can make and transfer calls on your staff's own devices.
• Emergency calls. Can every app and device call 999 and 112? How are registered addresses updated for staff working from home? Do not assume an app passes on an accurate live location.
• Broadband, support and uptime. Ask what the provider expects of your connection, what the support hours are, and what uptime commitment is written into the contract.
• Power cuts and continuity. Ask for an actual plan: backup power for the router, ONT and phones, mobile reception, automatic call diversion and broadband failover. A UPS will not help if the fault is further up the network. Also check alarms, door entry, fax machines and payment terminals that depend on the old line.
• Security. Look for multi-factor authentication for admin accounts, restricted international and premium rate calling, spend alerts and prompt patching. Ask who is responsible for responding to toll fraud. The NCSC's Small Business Guide covers the basics.

Drawing up a shortlist

1. List what you need: number of users, desk phones or apps, call queues, recording, phonebook and CRM link.
2. Pick two or three providers that fit, ideally from different routes above.
3. Trial them on real work, not just a test call.
4. Test call quality from your own office on your own broadband, at busy times of day.
5. Read the exit terms before you sign, including notice, number porting and getting your data back.

If you decide to run your own system, our 3CX setup articles take you through the practical side.