If you've still got a traditional phone system humming away in a cupboard, you're already on borrowed time. The PSTN switch-off means every UK business will be on an internet-based phone system by January 2027. That's not a marketing scare, it's an Openreach deadline.
So the question isn't really "should we move to VoIP". The question is "how do we do it without breaking how the business takes calls". Here is what you actually need to know.
What VoIP actually is (briefly)
VoIP, Voice over Internet Protocol, means your phone calls travel over your internet connection instead of a dedicated phone line. The phones themselves can be physical desk handsets, software on a laptop, an app on a mobile, or any combination. Same call, just a different pipe.
For most UK SMEs in 2026, this means one of three options:
- Microsoft Teams Phone, calling built into the Microsoft 365 client you already use
- 3CX, a dedicated VoIP platform with its own apps and admin interface
- A hosted PBX from a telco, Gamma, BT Cloud Voice, etc.
We've written a detailed comparison of Teams Phone vs 3CX for business, worth a read if you're choosing.
Why most businesses are moving (beyond the deadline)
Even without the PSTN switch-off, the case is strong:
- Lower line rental. No per-line costs, no per-minute geographic call charges between sites.
- Numbers travel with you. A Birmingham number on a phone in Manchester is fine.
- Mobile and desk become one experience. Your number rings on whatever you've got.
- Better admin. You can change a hunt group from a web browser instead of waiting for an engineer visit.
- Integrations. Click to dial from your CRM, automatic call logging, voicemail to email.
The hidden one nobody talks about: VoIP makes hybrid working actually work. The same person can take a call at their desk, on their laptop at home and on their phone in a car park. The customer never knows.
What you need to plan for before signing anything
This is where most VoIP projects go wrong. Skip these and you'll have a bad experience regardless of the platform.
1. Your internet connection
VoIP eats internet. Not a lot per call (about 100kbps), but it cares deeply about consistency. A flaky 50Mb broadband line that does fine for browsing will sound terrible on calls.
What you actually need:
- A business-grade connection with low jitter and packet loss (not a consumer fibre product)
- A second connection as failover, ideally on a different carrier
- A router that supports QoS so voice traffic gets priority
- Realistically, a wired network for desk handsets, patchy WiFi is the single most common cause of bad call quality
If you're going to skimp anywhere, don't skimp here.
2. Your existing phone numbers
The number transfer process is called porting. It usually takes 10–20 working days from the request being submitted, and the existing provider has to approve it.
Things that go wrong:
- The contract with the existing provider doesn't allow porting before a certain date
- The numbers are billed under a parent company name that doesn't match your trading name
- A geographic number is being moved outside its original area (sometimes blocked)
A good migration provider handles all of this, but you need to start the porting process before the cutover date, not on it.
3. Handsets and headsets
Three options:
- Use your laptops/mobiles only (cheapest, best for client-facing teams)
- Headsets only (good middle ground, especially with USB-C plug-and-play)
- Desk phones (best for reception, finance, anyone fielding lots of calls)
Both Teams and 3CX support certified Yealink, Polycom and Snom handsets. If you want desk phones, factor in £80–£200 each plus deployment time. Reception desks usually need a multi-line model.
4. Call flows, hunt groups and out-of-hours
This is the bit that catches everyone. You probably have:
- A main number that goes to a receptionist, then a hunt group, then voicemail
- Different routing for outside business hours
- Maybe an IVR ("press 1 for sales...")
- Probably a couple of direct dial numbers (DDIs) to specific staff
All of this needs to be mapped out before migration, not figured out on the day. We always document the existing flow first, agree the new flow, then build it once.
5. Emergency calls and address registration
Modern UK VoIP requires you to register the address each handset is at, so 999 calls route correctly. This is a legal/regulatory requirement, not a nice-to-have. Your provider should handle the registration but you need to give them accurate addresses for every site.
The contract gotchas to watch for
Three to flag specifically:
- Length. A 36-month contract on something that's evolving this fast is a long commitment. We prefer 12 months wherever the per-month price is reasonable.
- Per-user vs per-channel pricing. Per-user is usually cleaner for SMEs. Per-channel can save money if you have lots of staff who barely use the phone.
- What's included in calling. UK landlines and mobiles bundled is now standard; international and premium-rate calls are usually metered. Check before assuming.
How long the actual migration takes
For a typical 20–50 person business:
- Week 1: discovery, design, port request submitted
- Weeks 2–4: build the new platform, configure call flows, prepare handsets, train staff
- Week 5–6: port date, cutover, parallel running for a few days, snag-list
The porting timeline (set by the carriers, not us) is almost always the bottleneck. Everything else can be compressed if needed.
The honest bit
VoIP is genuinely better than legacy phone systems for almost every SME. It's also a project that goes badly when treated as a quick swap. The businesses that have a smooth migration are the ones that planned the call flows, sorted the network, and didn't skip the porting paperwork.
Our Communications and VoIP service covers all of the above for Birmingham and West Midlands businesses, including the bit where we actually visit your office, see the network, and tell you if anything needs fixing first.
Or book a 15-minute call if you'd rather just talk it through.