Business Phone Lines UK 2026: The Complete Comparison Guide
Choosing the right business phone lines has never been more consequential. With the PSTN switch-off now well underway and Openreach’s all-IP network rapidly replacing legacy infrastructure, every UK business must evaluate its telephony strategy — whether you’re a sole trader needing a single business telephone line or a multi-site enterprise managing hundreds of extensions.
In this comprehensive guide, we compare the four main types of business phone line available in 2026 — traditional landlines, VoIP, virtual numbers, and SIP trunks — side by side. We’ll cover monthly costs, setup fees, features, and the migration path we recommend to future-proof your communications.
Understanding Business Phone Line Types in 2026
Before diving into the comparison, it’s worth understanding exactly what each technology offers and where it fits in the modern business landscape.
Traditional Landlines (PSTN/ISDN)
Traditional analogue landlines have served UK businesses reliably for decades. They operate over the Public Switched Telephone Network (PSTN) using copper wiring from your premises to the local exchange. ISDN (Integrated Services Digital Network) lines offered a digital upgrade, supporting multiple channels over a single connection.
Critical update for 2026: Openreach has confirmed that all PSTN and ISDN services will be fully switched off by January 2027. New PSTN/ISDN connections are no longer available in most exchange areas. If your business still relies on traditional landlines, migration to an IP-based alternative is now urgent.
VoIP Business Phone Lines
Voice over Internet Protocol (VoIP) transmits calls over your broadband connection rather than copper phone lines. Hosted VoIP — where the platform is managed in the cloud by your provider — has become the default choice for UK businesses of all sizes. It delivers enterprise-grade calling features at a fraction of the cost of legacy systems.
Virtual Phone Numbers
Virtual numbers are telephone numbers not tied to a specific physical line or device. Incoming calls to a virtual number are forwarded to a destination of your choice — a mobile, a VoIP handset, or a call group. They’re ideal for establishing local or national presence without additional hardware.
SIP Trunks
SIP (Session Initiation Protocol) trunking connects your existing on-premises PBX telephone system to the internet, replacing ISDN lines. It’s a bridge technology that lets businesses retain their current PBX hardware while benefiting from IP-based calling. SIP trunks are particularly popular with larger organisations that have recently invested in on-site PBX equipment.
Business Phone Lines: Feature and Cost Comparison Table
The table below provides a side-by-side comparison of the four business phone line types, covering typical UK costs and capabilities in 2026.
| Feature | Traditional Landline | VoIP (Hosted) | Virtual Numbers | SIP Trunks |
|---|---|---|---|---|
| Monthly cost per line | £25–£40 | £6–£18 | £2–£8 | £4–£12 per channel |
| Typical setup fee | £50–£150 | £0–£50 | £0–£10 | £0–£75 |
| Call inclusive minutes | Varies by package | Unlimited UK often included | Forwarding charges apply | Per-minute or bundled |
| Call recording | ❌ Add-on required | ✅ Included | ❌ Rarely available | ⚠️ PBX-dependent |
| Auto-attendant / IVR | ❌ | ✅ Included | ⚠️ Basic | ⚠️ PBX-dependent |
| Mobile app integration | ❌ | ✅ Full softphone | ⚠️ Call forwarding only | ❌ |
| Video conferencing | ❌ | ✅ Often included | ❌ | ❌ |
| Scalability | Poor (physical install) | Excellent (instant) | Excellent (instant) | Good (provider-managed) |
| PSTN switch-off impact | Service will cease | No impact | No impact | No impact |
| Recommended for | No longer recommended | Most UK businesses | Startups, remote teams, marketing | Businesses with existing PBX |
The PSTN Switch-Off: Why Your Business Phone Line Strategy Must Change
The biggest factor influencing business phone lines in 2026 is the PSTN and ISDN switch-off. Openreach — the infrastructure arm of BT — is retiring the copper-based telephone network that has underpinned UK communications since the 20th century. Here’s what you need to know:
- No new PSTN/ISDN orders: Openreach stopped accepting new analogue and ISDN line orders across most of the UK in September 2023.
- Full switch-off by January 2027: All remaining PSTN and ISDN services will be permanently disconnected.
- Number porting is available: You can keep your existing business telephone numbers when migrating to VoIP or SIP — your customers won’t notice any change.
- Non-voice services affected: PSTN lines used for alarm systems, EPOS machines, fax lines, and lift emergency phones must also be migrated.
If your business hasn’t yet planned its migration, time is running short. Connection Technologies has helped hundreds of UK businesses transition smoothly from legacy phone lines to modern VoIP solutions — with zero downtime and full number portability.
Why VoIP Is the Recommended Business Phone Line for 2026
For the vast majority of UK businesses, hosted VoIP is now the clear winner. Here’s why we recommend it as the default business phone line technology:
1. Significant Cost Savings
VoIP business phone lines typically cost 50–70% less than traditional landlines. With per-seat pricing from as little as £6 per month, unlimited UK calls often included, and minimal setup fees, the economics are compelling. Most businesses see a return on investment within the first quarter of switching.
2. Enterprise Features as Standard
Hosted VoIP platforms include features that were once exclusive to enterprise-grade PBX systems: auto-attendant menus, call queues, ring groups, voicemail-to-email, call recording, real-time analytics, CRM integration, and presence management. These come included in the monthly subscription rather than as costly add-ons.
3. Complete Flexibility and Mobility
Modern VoIP systems work seamlessly across desk phones, laptops, tablets, and smartphones via softphone apps. Your team can make and receive calls on their business telephone line number from anywhere with an internet connection — essential for hybrid and remote working environments.
4. Effortless Scalability
Adding a new user or phone line to a VoIP system takes minutes, not weeks. There’s no waiting for an engineer visit or physical line installation. This makes VoIP ideal for growing businesses and those with seasonal demand fluctuations.
5. Future-Proof Technology
VoIP is entirely unaffected by the PSTN switch-off. By migrating now, your business avoids last-minute disruption and positions itself on the same communications platform that will serve you for the next decade and beyond.
When to Choose Virtual Numbers or SIP Trunks
While VoIP is the right choice for most businesses, virtual numbers and SIP trunks serve specific use cases effectively.
Virtual Numbers: Best for Presence and Marketing
Virtual numbers are ideal when you need local geographic numbers (e.g., a London 020 number or a Manchester 0161 number) without having a physical office in that location. They’re also excellent for tracking marketing campaign responses, providing dedicated customer service lines, or giving individual team members direct dial numbers at minimal cost.
Many businesses use virtual numbers alongside a core VoIP system — they’re complementary rather than competing technologies.
SIP Trunks: Best for Existing PBX Investments
If your business has invested significantly in an on-premises PBX system that’s still functioning well, SIP trunking allows you to keep that hardware while replacing your ISDN lines with internet-based connections. This can be a cost-effective interim step, particularly for larger organisations where a full hosted VoIP migration requires more planning time.
However, it’s worth noting that SIP trunking still requires you to maintain and manage physical PBX equipment — with its associated maintenance costs and eventual obsolescence. For most businesses, a full move to hosted VoIP is the smarter long-term investment.
Your Recommended VoIP Migration Path
At Connection Technologies, we’ve refined a straightforward migration process that minimises disruption and maximises the value of your new business phone lines:
- Audit your current setup: We review your existing phone lines, call volumes, and feature requirements to recommend the optimal VoIP configuration.
- Broadband assessment: We check your internet connectivity to ensure it can support high-quality VoIP calls. If needed, we can upgrade your broadband as part of the project.
- System design and configuration: We build your VoIP system to match your call flow requirements — auto-attendants, hunt groups, call queues, and user extensions.
- Number porting: We manage the transfer of your existing business telephone numbers to the new platform, ensuring no interruption to incoming calls.
- Hardware provisioning: If you need desk phones, we supply pre-configured handsets ready to plug in. Many users prefer softphone apps on their computers or mobiles — no hardware required.
- Go live and support: We manage the cutover, provide user training, and deliver ongoing UK-based support from our dedicated team.
The entire process typically takes two to four weeks, depending on the complexity of your setup and the number porting timeline.
How to Choose the Right Business Phone Line Provider
When comparing providers for your business phone lines, consider the following criteria:
- UK-based support: Ensure your provider offers responsive, knowledgeable support from a UK team — not an overseas call centre.
- Transparent pricing: Look for clear per-user pricing with no hidden fees for essential features like call recording or auto-attendant.
- Number porting expertise: Your provider should handle number porting seamlessly and have experience managing complex multi-number migrations.
- Connectivity options: The best providers, like Connection Technologies, can supply both your business broadband and VoIP — ensuring the underlying connection is optimised for voice traffic.
- Scalability and contract flexibility: Choose a provider that lets you add or remove users easily without punitive contract terms.
- Integration capabilities: If you use CRM software, helpdesk tools, or Microsoft Teams, check that the VoIP platform integrates smoothly.
Frequently Asked Questions
How much does a business phone line cost in the UK in 2026?
The cost depends on the technology. Traditional landlines cost £25–£40 per month (where still available), while VoIP business phone lines typically range from £6–£18 per user per month with significantly more features included. Virtual numbers can cost as little as £2–£8 per month. For most businesses, VoIP offers the best value.
Can I keep my existing business phone number when switching to VoIP?
Yes. Number porting allows you to transfer your existing business telephone numbers to a new VoIP provider. The process typically takes 7–14 working days in the UK, and your customers won’t notice any change. Connection Technologies manages the entire porting process on your behalf.
What happens to my business phone line after the PSTN switch-off?
If you’re still using a traditional PSTN or ISDN business phone line, the service will cease to function when Openreach completes the switch-off in your area (fully complete by January 2027). You must migrate to an IP-based alternative — such as VoIP or SIP trunking — before this date to maintain your telephone service.
Is VoIP reliable enough for business use?
Modern hosted VoIP platforms are extremely reliable, with most reputable providers offering 99.99% uptime SLAs. Call quality on a decent broadband connection is indistinguishable from — and often better than — traditional landlines. VoIP also has built-in resilience: if your office internet goes down, calls can automatically failover to mobile devices.
What broadband speed do I need for VoIP business phone lines?
Each concurrent VoIP call requires approximately 100 Kbps of bandwidth in both directions. A standard fibre broadband connection can comfortably support 20+ simultaneous calls. For businesses with high call volumes, Connection Technologies can recommend dedicated or leased line connectivity to guarantee call quality.
What is the difference between VoIP and SIP trunking?
Hosted VoIP is a complete cloud-based phone system — everything is managed by your provider, and you simply need handsets or softphone apps. SIP trunking connects an existing on-premises PBX system to the internet, replacing ISDN lines. VoIP is simpler to manage and lower in total cost; SIP trunking is useful for businesses that want to retain existing PBX hardware.
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