Your business phone number is one of the most valuable unseen assets your business owns. It's on your van, your invoices, your Google listing, your business cards, your shop front, and a decade of marketing that customers have filed away in their phones under your company name. Losing it isn't an inconvenience — it's losing the audible handle that every past, present, and future customer uses to find you.
So when it comes time to move away from your traditional landline — whether that's because of the PSTN switch-off, a cost-saving decision, or simply because you've outgrown a phone that sits on a desk — the number needs to come with you. The technical name for moving it is "porting", and this guide is the complete, boring-but-useful walkthrough of exactly how UK number porting works, what can go wrong, and how to get through it without losing a call.
What Number Porting Actually Is
Number porting is the formal process of transferring a phone number from one provider (the "losing" provider in industry terminology) to another (the "gaining" provider). The number itself stays the same. What changes is which company's network the number lives on, and therefore which company's equipment answers calls to that number.
Under UK regulation, every licensed telecoms provider has to allow customers to port their numbers out on request. This isn't a favour they're doing you — it's a legal obligation set by Ofcom. That means BT, Virgin Business, Sky, TalkTalk, Gamma, Daisy, Plusnet, Post Office, and every smaller reseller are all required to release numbers when a valid port request is submitted by a gaining provider on your behalf.
The mechanics happen entirely between the two providers. You sign a short authorisation document to give permission, provide a handful of account details, and then the two companies coordinate in the background. You don't have to handle any of the inter-provider communication yourself.
Why You Should Keep Your Existing Number
Before we get into the how, it's worth being clear on the why — because some businesses, when faced with a phone system change, decide "it's just easier to take a new number". For most small businesses, that decision is significantly more expensive than they realise.
Vehicle Signage
Re-wrapping or re-signing a van, fleet, or shop front typically costs £300–£1,000+ per vehicle or site.
Marketing Collateral
Business cards, flyers, letterheads, invoices, brochures — all need reprinting at real cost.
Google & Online Listings
Google Business, directories, Checkatrade, Yell, and review sites all need updating and sometimes re-verifying.
Saved Contacts
Every past customer has your old number in their phone. A new number means you stop getting repeat calls from them.
Backlinks & SEO Signals
Directories, partner sites, and review pages often cite your number. New number = reduced trust signals.
Word of Mouth
Recommendations go "ring Dave on 01625…" — a new number means every recommendation fails silently.
Add it up, and the cost of abandoning an established business number can easily run to several thousand pounds of real spend plus a long tail of lost repeat business. Porting, by contrast, is free through Team-Connect and takes fifteen minutes of your time. It's not a close decision.
Which UK Numbers Can Be Ported
The UK numbering plan covers a range of different number types, and the rules for porting vary slightly between them. The practical answer for almost every small business: yes, your number can be ported. Here's the breakdown:
- 01 and 02 geographic numbers — the classic UK landline format (01625, 0161, 020, etc.) — are fully portable and the most common type of port Team-Connect handles.
- 03 non-geographic numbers (0300, 0330, 0333, 0345, 0370, etc.) are portable between providers.
- 0800 and 0808 freephone numbers are portable, though the process can involve additional paperwork depending on the current provider.
- 0844, 0845, 0870, 0871, 0872 revenue-share numbers are technically portable but are gradually being phased out; we'd usually suggest moving to an 03 replacement rather than keeping these.
- Mobile numbers (07) are portable between mobile networks and increasingly between mobile and VoIP services, though the specifics vary.
If you've got something unusual — a legacy shared-cost number, an old ISDN range, a block of DDI numbers from a large PBX — Team-Connect can still usually port it, but the timeline may be longer and may need a quick chat before the standard sign-up flow.
What You Need Before You Start
A port request needs specific pieces of information, and they all need to match exactly what your current provider has on file. The single most common reason a port is rejected is a tiny mismatch between what you submit and what's on the losing provider's system — a different trading name, a typo in the account number, or the service address being slightly different to the billing address.
Dig out a recent bill from your current provider before you start. Every piece of information below should be taken from that bill, not from memory or from a website. This one piece of prep will save you a rejected port and a week of delay.
Specifically, you'll need:
- The phone number(s) being ported — written exactly as they appear on the bill, including the leading zero.
- The current provider's name — the actual legal entity on the bill, which isn't always the brand name you know them by. For example, many small-business BT lines are billed by "BT Business" or "EE Limited". Virgin business is often "Virgin Media Business".
- Your account number with that provider — usually on the first page of the bill.
- The account holder name — exactly as it appears on the bill. If it's a limited company, it needs to match the registered name. If it's a sole trader, it needs to match the personal name on the account.
- The service address — the physical address the line is registered to, which isn't always where the phone is physically used.
The Step-by-Step Porting Process
Here's exactly what happens, from the moment you decide to port to the moment calls start ringing on your new system.
Step 1 — Sign up with Team-Connect
Head to the sign-up page, choose your plan, and create your account. You can do this entirely from your mobile in a couple of minutes. At this point, your new Team-Connect setup is live with a temporary number so you can start configuring everything — but your existing number is still running on your current provider's system.
Step 2 — Start the port request
From your Team-Connect dashboard, choose "Port in an existing number" and enter the details from your current bill. The system will validate the format of the number, check your provider is one we can port from, and generate the Letter of Authorisation ready for you to sign.
Step 3 — Sign the LOA digitally
The Letter of Authorisation is a short legal document that tells your current provider "I authorise Team-Connect to request the transfer of this number on my behalf". You sign it digitally inside the dashboard — no printing, no posting. The LOA is then sent to your losing provider as part of the port request.
Step 4 — Losing provider validation
Your current provider receives the request and checks the details match their records. If everything matches, they'll accept the port and propose a cutover date. If anything mismatches, the port is rejected with a reason, and we'll come back to you to correct the detail that's wrong. Validation typically takes 2–5 working days.
Step 5 — Port date confirmed
Once accepted, you'll get a confirmed cutover date, usually 5–10 working days further out. Your existing line carries on working normally throughout this period — customers calling your number still reach your old system right up until cutover. You can use this time to fully configure your greeting, AI receptionist, business hours, and call flow so everything is ready.
Step 6 — Cutover morning
Ports almost always happen in the early morning, typically between 07:00 and 09:00. During a short window of a few minutes, your number stops routing to the old provider and starts routing to Team-Connect. Calls placed after cutover ring on your mobile through the Team-Connect app.
Step 7 — Cancel the old line
Only after Team-Connect has confirmed the port has completed successfully, contact your old provider and cancel the underlying line and any associated services. Don't do this before. Don't do it the same day as cutover. Wait for the confirmation.
The LOA (Letter of Authorisation) Explained
The LOA is the single piece of paperwork that sits at the heart of every UK number port, and it trips people up more often than it should — usually because it's the one bit of the process where the legal language can feel a bit intimidating.
In plain terms, it's a short document that contains the number being ported, your account details, the losing provider's name, and a statement that you authorise the gaining provider to act on your behalf to request the transfer. That's it. It's not a contract with your old provider, it's not a cancellation notice, and it doesn't terminate any services on its own.
With Team-Connect, the LOA is generated automatically from the details you enter during the port request and is signed digitally in the dashboard. There's no PDF to download, no pen-and-paper signature, no scanning, no posting, and no waiting for a form to arrive in the post. The whole thing takes less than a minute.
Timelines by Provider
Porting timelines vary depending on who you're porting from. These are typical ranges based on what we see — individual cases can be faster or slower depending on provider workload and whether any details need re-checking.
The most important thing to understand about timelines: your current service keeps working the entire time. The "5 to 15 working days" isn't downtime — it's a scheduling window during which your number stays on your old provider. Calls come in normally, you make calls normally, nothing changes from the customer's perspective until the actual cutover morning.
What Happens on Cutover Day
The port itself is an underwhelming event, which is exactly what you want. You'll receive a confirmation before the day telling you which morning the cutover is scheduled for. On the day itself, your number stops responding on the old provider's network during a short window, and starts routing to Team-Connect.
From that moment on, every incoming call to your number rings on your mobile through the Team-Connect app. The AI receptionist, if you've configured it, starts handling calls according to the rules you've set. Outbound calls you make through the Team-Connect app show your business number to the recipient. The only thing that's changed, from a customer's perspective, is that the person answering the call is now holding a mobile in their kitchen or their van rather than a handset on a desk.
If you're expecting calls at the exact time of cutover, there's a very small possibility (usually under a minute) where a call could fail as routing switches. It's rare, but if you're particularly sensitive to it, schedule important calls for later in the morning.
The Five Mistakes That Lose Businesses Their Number
We see every one of these repeatedly. They're all avoidable, and they're all the difference between a smooth port and a phone call to a previous provider begging them to reverse a cease order.
- Cancelling the old line before the port completes
- Letting an unpaid bill cease the line mid-port
- Providing mismatched account details
- Port requested after the switch-off date for PSTN lines
- Buying a "replacement" number and letting the original lapse
- Wait for port confirmation before cancelling anything
- Keep the old account in good standing until cutover
- Copy every detail directly from a recent bill
- Start the port well before any switch-off deadline
- Port first, then set up any new secondary numbers
Mistake 1: Cancelling the old line first
This is the big one. A ceased number can't be ported — it's been released back into the pool and may not be recoverable at all. Always wait until your new provider confirms the port is complete before cancelling anything.
Mistake 2: Letting a bill lapse during the port window
If your old line gets ceased for non-payment during the port process, the port will fail and the number will be at risk. Keep the account current until after cutover, even if you've already decided you're leaving.
Mistake 3: Getting the account details wrong
Tiny mismatches reject ports. "J Smith Plumbing" vs "John Smith Plumbing Ltd" will fail. Always copy from a recent bill, not from memory.
Mistake 4: Leaving the port too late before a switch-off
If your line is due to be ceased as part of the PSTN switch-off, start your port at least 30 days before the switch-off date. Pushing it closer risks the line being ceased before the port completes.
Mistake 5: Getting a new number "just to get going"
Some businesses, impatient to start using the new system, take a temporary number and plan to "sort the old number out later". This is fine in principle, but don't let the old line lapse in the meantime. Port first, then the rest is easy.
What to Do After the Port Completes
Once the port is done and calls are flowing on your new system, there's a short checklist worth running through to tidy up:
- Cancel the old line formally. Call your previous provider, give them the account number, and instruct them to terminate the service. Ask for confirmation in writing or email.
- Cancel any associated services tied to the old line. Broadband, line rental bundles, calling plans, and any old feature packs.
- Test inbound and outbound. Call your number from another phone to make sure it rings correctly. Make an outbound call to make sure your number shows as the caller ID.
- Configure your AI receptionist fully. Greeting, hours, out-of-hours handling, what to do with voicemails and transcripts.
- Tell your team. If others in the business answer calls, make sure they've got the app installed and know how it works.
- Test your alarm, card terminal, and any other equipment that might have been piggybacking on the old line. With the PSTN being switched off, anything still dependent on the old network needs its own replacement plan.
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Frequently Asked Questions
Can I keep my existing business landline number when I switch to a mobile-based phone system?
Yes. UK number portability rules give you the legal right to take your number with you when changing providers. Geographic numbers (01 and 02), non-geographic numbers (03), and most 0800 and 0845 numbers are portable. Once the port completes, your original business number will ring on your mobile through your new provider's app.
How long does it take to port a UK business number?
Most ports complete in 5 to 15 working days. Ports from major providers like BT, Virgin Business, Sky, and TalkTalk typically take 7 to 10 working days. Ports from smaller resellers can occasionally take up to 20 working days. Your existing line keeps working throughout, so there is no service interruption while you wait.
What is a Letter of Authorisation and do I need one?
A Letter of Authorisation, or LOA, is a short document that gives your new provider permission to request the transfer of your number from your current provider. It's a standard and legally required part of UK number porting. With Team-Connect, the LOA is generated and signed digitally inside the sign-up flow, so there's no paper form to print or post.
How much does it cost to port a business phone number in the UK?
Porting fees vary by provider. Team-Connect ports standard UK geographic and non-geographic numbers at no cost as part of the sign-up process. Your existing provider may apply early termination charges if you leave within a minimum contract period — this is separate from the porting fee itself and is a matter between you and your current provider.
Will my phone service go down during the port?
No, not if the port is managed correctly. Your existing line stays fully active right up until the scheduled cutover time, at which point calls start routing to your new provider. The changeover typically happens in the early morning and is usually complete within a few minutes. Well-managed ports from Team-Connect result in no missed calls and no noticeable interruption.
Can I port my number from BT, Virgin, Sky, TalkTalk or another provider?
Yes. All major UK providers are required under Ofcom rules to allow their customers to port numbers out on request. Team-Connect accepts ports from BT, Virgin Business, Sky, TalkTalk, Vodafone, Gamma, Plusnet, Post Office, Daisy, and almost every other UK telecoms provider.
What information do I need to provide?
The phone number being ported, the name of your current provider, your account number with that provider, the account holder name exactly as it appears on your current bill, and the service address the line is registered to. Any mismatch between these details and the records held by your current provider can cause the port to reject.
What happens if I cancel my old line before the port completes?
This is one of the most common and damaging mistakes. If you cancel the old line before the port is complete, your number will be marked as ceased by your original provider and cannot be transferred. In most cases the number is lost permanently. Always wait until your new provider confirms the port is complete before cancelling anything on the old account.
Can the AI receptionist answer calls on my ported number straight away?
Yes. As soon as the port completes and calls are routing to Team-Connect, every feature on your plan is active on the ported number — including the 24/7 AI receptionist. You can configure your greeting, opening hours, and call flow before the port completes so everything is ready the moment the number switches across.
The Bottom Line
Porting is one of those processes that sounds technical and bureaucratic but is genuinely straightforward once you understand the sequence. Sign up. Submit the request. Sign the LOA. Wait for confirmation. Don't cancel anything early. That's essentially the whole thing. For the vast majority of UK small businesses, the port completes inside two weeks, with zero downtime, at no cost, and with the happy side effect of a far more capable phone system waiting at the other end.
If you're ready to get started, you can sign up and begin the port right now — the whole request can be submitted from your mobile in under fifteen minutes. If you'd rather chat it through first, especially if you've got anything unusual in your current setup, the Team-Connect team can walk you through the specifics.