Cloud Based Telephony UK 2026: What It Is, How It Works & How to Switch

Cloud based telephony is rapidly replacing traditional phone systems across the UK. Instead of relying on physical phone lines and on-premise hardware, cloud telephony routes your business calls over the internet — giving you more features, greater flexibility, and lower costs than the copper-wire systems it replaces.

With BT’s PSTN switch-off scheduled for January 2027, understanding cloud based telephony is no longer optional — it is essential. This guide explains what it is, how it works, what it costs, and how to make the switch. All prices quoted are ex-VAT.

What Is Cloud Based Telephony?

Cloud based telephony — also known as hosted VoIP, cloud PBX, or UCaaS — is a phone system that runs entirely in the cloud. Instead of a physical PBX box in your office connected to copper phone lines, your phone system is hosted on servers in secure data centres and accessed over your internet connection.

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Your desk phones, mobile apps, and computer softphones all connect to this cloud platform. When you make or receive a call, the voice data travels over the internet rather than over traditional phone lines. To the caller, the experience is identical — they dial your number and you answer. But behind the scenes, the technology is fundamentally different.

How Cloud Based Telephony Works

Understanding the technical basics helps you make better decisions about providers, broadband requirements, and network configuration. Here is a simplified explanation of how a cloud phone call works.

Voice to Data Conversion

When you speak into a VoIP phone (or a softphone app), your voice is captured by the microphone and converted from an analogue audio signal into digital data packets. This conversion happens using a codec — a compression algorithm that balances audio quality with bandwidth usage. The most common codec for business VoIP is G.711, which provides excellent call quality at approximately 87 Kbps per call.

Transmission Over the Internet

These data packets are sent over your broadband connection to your cloud telephony provider’s data centre. The packets travel via the public internet or, for higher-quality solutions, over a dedicated or MPLS connection. Quality of Service (QoS) settings on your router prioritise voice packets over other internet traffic to ensure consistent call quality.

Routing and Switching

At the provider’s data centre, the cloud PBX software handles all the routing logic — IVR menus, call queues, ring groups, voicemail, call recording, and forwarding rules. When an external caller dials your number, the call arrives at the data centre, is processed by the cloud PBX, and is routed to the correct extension, ring group, or auto-attendant based on your configuration.

Delivery to the Recipient

The routed call is delivered to the destination device — whether that is a desk phone in your office, a mobile app on a smartphone in a coffee shop, or a softphone on a laptop at home. Because the system is cloud-based, it does not matter where the user physically is — calls follow the user, not the location.

Cloud vs Traditional Telephony: A Direct Comparison

Key Features of Cloud Based Telephony

One of the biggest advantages of cloud telephony over traditional systems is the breadth of features available as standard. Here are the features that deliver the most value to UK businesses.

Auto-Attendant (IVR)

An auto-attendant greets callers with a professional recorded message and presents menu options — “Press 1 for sales, 2 for support, 3 for accounts.” This routes calls to the right department without a receptionist, ensures calls are never missed, and presents a professional image even for small businesses. Most cloud platforms let you configure multiple levels of menus, time-based routing (different menus for office hours vs out-of-hours), and custom greetings.

Call Recording

Automatic call recording is invaluable for training, quality assurance, compliance (particularly in regulated industries), and dispute resolution. Cloud platforms store recordings securely in the cloud, searchable by date, user, or phone number. Storage periods vary — some providers include 12 months of storage, while others offer unlimited retention.

Mobile App

A business mobile app lets your team make and receive calls on their business phone number using their personal smartphone. The caller sees your business number on their screen, not your employee’s personal mobile number. This is essential for remote and hybrid workers, field-based staff, and anyone who needs to remain professionally contactable outside the office.

Call Analytics and Reporting

Cloud telephony platforms provide detailed analytics on call volumes, wait times, missed calls, call duration, and agent performance. This data helps you identify peak call times, staff your team appropriately, spot training needs, and understand customer calling patterns. For sales teams, call analytics can directly correlate calling activity with revenue outcomes.

CRM and Business Tool Integration

Integration with your CRM (Salesforce, HubSpot, Microsoft Dynamics, Zoho) and other business tools automates call logging, provides screen pops with customer information during inbound calls, and enables click-to-dial from contact records. This saves time, reduces errors, and gives your team context before they even pick up the phone.

Video Conferencing

Many cloud telephony platforms now include video conferencing as standard, eliminating the need for a separate tool like Zoom or Google Meet. Having voice, video, and messaging in a single platform simplifies your technology stack and reduces costs.

How to Switch to Cloud Based Telephony

Switching from a traditional phone system to cloud based telephony is a straightforward process when managed properly. Here are the steps involved.

Step 1: Assess Your Current Setup

Document your existing phone numbers (geographic, non-geographic, and mobile), the number of extensions, your current call flows and routing rules, and any hardware that might be reusable. This information forms the basis of your migration plan.

Step 2: Check Your Broadband

Cloud telephony depends on your internet connection. You need sufficient bandwidth (approximately 100 Kbps per concurrent call), low latency (under 150ms), low jitter (under 30ms), and consistent performance. If your current broadband is unreliable, upgrading it should be part of your migration plan. A reputable provider will test your connection before recommending a solution.

Step 3: Choose Your Provider

Evaluate providers based on features, pricing, call quality, support, and contract flexibility. Request demos from your shortlisted providers and test the mobile app, call quality, and admin portal yourself. Check references from existing clients in similar industries.

Step 4: Configure and Test

Your provider will configure the system based on your requirements — setting up users, extensions, call flows, auto-attendant menus, ring groups, and integrations. Thorough testing before go-live is essential: test inbound and outbound calls, call transfers, voicemail, the mobile app, and any integrations.

Step 5: Port Your Numbers and Go Live

Number porting transfers your existing phone numbers to the new platform. Geographic number porting takes 1–2 weeks in the UK. During the port, calls are automatically redirected to your new system. Once porting is complete and everything is tested, your migration is done.

Choosing the Right Cloud Telephony Provider

With dozens of providers in the UK market, choosing the right one requires careful evaluation. The three most important factors are call quality, feature depth, and support quality — and these are far more important than headline price.

What to Ask in Your Evaluation

• Where are your data centres located? UK-based data centres ensure lower latency and compliance with UK data protection regulations. Look for providers with at least two UK data centres for redundancy
• What is your uptime SLA? Anything below 99.99% is substandard for a business-critical system. Ask for historical uptime data, not just the contractual SLA
• How do you handle number porting? A good provider will project-manage the entire porting process, coordinate dates with your current provider, and ensure zero downtime during the transition
• What training and onboarding do you provide? A system is only as good as the people using it. Look for providers who include comprehensive onboarding and ongoing training as part of the subscription
• What does your support look like? Do you get a named account manager or a generic helpdesk? What are the support hours? Is there a UK-based support team?

Costs: What to Expect

Cloud based telephony is typically significantly cheaper than traditional phone systems when you factor in total cost of ownership. Here is a realistic cost breakdown for a 20-user business.

• Per-user licence: £6–£15/user/month depending on provider and feature tier. For 20 users, that is £120–£300/month
• IP desk phones (if needed): £50–£250 per handset as a one-off cost. Entry-level Yealink phones start at around £50; premium Poly models with colour screens cost £200+. Many businesses skip desk phones entirely and use softphone apps
• Broadband (if upgrade needed): Business FTTC from £20/mo; FTTP from £30/mo; leased line from £200/mo. Your existing broadband may already be sufficient
• Number porting: Usually included free by the provider. Some charge a small fee (£5–£10 per number)
• Setup and configuration: Often included in the subscription. Some providers charge a one-off setup fee of £100–£500
• Training: Typically included. Allow 30–60 minutes per user for initial training

For a typical 20-user SME switching from traditional lines, the total monthly cost of cloud telephony is £120–£300/month compared to £300–£500/month for the old system — a saving of £2,000–£4,000 per year before you even factor in the productivity benefits of advanced features.

Frequently Asked Questions

What happens if the internet goes down?

Cloud telephony platforms include automatic failover. If your broadband drops, calls can be instantly redirected to mobile phones, an alternative site, or a voicemail system. You can configure failover rules in advance so the redirection happens automatically. Some businesses keep a 4G backup broadband connection specifically for this scenario — a 4G router costs £20–£30/month and provides a safety net for both voice and data.

Is cloud telephony secure?

Yes. Reputable providers encrypt all voice traffic using TLS and SRTP protocols, the same encryption standards used by online banking. Data centres are ISO 27001 certified, and access controls ensure only authorised users can manage the system. Cloud telephony is generally more secure than traditional phone lines, which had no encryption at all.

Do I need new phones?

Not necessarily. If you have existing SIP-compatible IP phones, they can usually be reconfigured for your new cloud platform. If you have analogue phones, you will need either new IP phones or analogue telephone adapters. Alternatively, many businesses now rely entirely on softphone apps on computers and smartphones, eliminating the need for desk phones altogether.

Can I keep my phone numbers?

Yes. All UK phone numbers — geographic (01/02), non-geographic (03), and mobile — can be ported to a cloud telephony platform. The process is managed by your new provider and typically takes 1–2 weeks for geographic numbers.

What broadband speed do I need?

Each concurrent VoIP call uses approximately 100 Kbps. For a 10-person office where 5 people might be on calls simultaneously, you need about 500 Kbps dedicated to voice traffic. A standard FTTC connection (36–80 Mbps) is more than sufficient for most small to medium offices. Larger deployments with 50+ concurrent calls should consider FTTP or a leased line.

How reliable is cloud telephony compared to traditional lines?

Leading cloud telephony platforms deliver 99.99% uptime, which equates to less than 53 minutes of downtime per year. Traditional PSTN lines were reliable but had no redundancy — if the line was damaged, you had no phone service until it was repaired. Cloud telephony with automatic failover to mobiles is actually more resilient than the old system.

The Bottom Line

Cloud based telephony is not just the future of business communications — it is the present. With the PSTN switch-off looming in January 2027, every UK business needs to make the move, and those who do it now benefit from lower costs, better features, and a smoother transition than those who leave it to the last minute.

The technology is mature, reliable, and proven. Millions of UK businesses already use cloud telephony daily. The key is choosing a provider that offers the right balance of features, call quality, support, and value for your specific needs.

Whether you are a 5-person startup or a 500-person enterprise, cloud based telephony can transform how your business communicates — externally with customers and internally across teams and locations. The question is no longer “should we switch?” but “who should we switch to?”