The best BT One Phone alternative keeps your business landline number working on the mobile you already carry, with no second device, no second SIM, no second contract. Solofone does exactly that: it gives UK small businesses a proper landline number, plus WhatsApp Business on the same number, on the phone you already have. And timing matters here: BT One Phone was withdrawn in March 2026, a shutdown BT confirmed on its own business support forum, so any business still relying on it needs a replacement now.
For years, the default answer was BT One Phone, a system that turned your landline number into a second mobile. It worked, but it meant carrying two phones everywhere. Two phones to charge. Two phones to answer. Two numbers to give out and keep straight. And on top of that, you were paying for a second device and a second contract.
There's a simpler way to handle the landline switch off as a small business, and it doesn't involve buying anything extra.
What Happened to BT One Phone?
BT withdrew One Phone in March 2026. The service, which turned a business landline number into a second mobile on its own SIM, was closed down and customers were pointed at BT Cloud Voice instead. Cloud Voice is a different kind of product: it's built around desk phones, VoIP apps and a new multi-year contract, and customers on BT's own support forum report being pushed to move across quickly or face early termination charges.
For a small business that just wanted its business number answered, that's a lot of upheaval for something that used to be simple. It also explains why so many people are searching for a BT One Phone alternative that doesn't mean new hardware, a new handset or another long contract. The good news: the number itself is not lost. UK numbers can be moved between providers, so the landline number your customers already know can come with you.
Do I Need a Second Phone to Replace BT One Phone?
No. Solofone puts your business landline number directly on the mobile you already carry. No second SIM. No second device. No juggling two phones.
Here's how it works: you get a proper UK landline number, but it rings straight through to your existing mobile. Customers dial your business number like normal. You answer on the phone that's already in your hand.
That's the whole idea behind separating your work and personal phone number without needing two phones to do it.
Can I Use WhatsApp Business on My BT One Phone Replacement Number?
Yes. With Solofone, your business number works as a WhatsApp Business landline number too. Same number, same phone, one place for everything. No separate WhatsApp number to manage, no confusion about which number customers should message.
That matters, because most small businesses these days get almost as many enquiries through WhatsApp as they do phone calls. Customers want to send a quick message, share a photo of the job, or ask a question without picking up the phone at all.
What Happens to Business Calls Outside My Working Hours?
Solofone answers them for you. You set your business hours in the app. During those hours, calls come straight to you. Outside those hours (evenings, weekends, when you're on a job, when you're having dinner with your family) Solofone picks up on your behalf.
This is where it gets useful for anyone running a small business on their own: tradespeople, salon owners, consultants, anyone who doesn't have a receptionist sitting by the phone all day. And it works the same wherever you are, whether that's a consultancy in London or a trade business covering half of Yorkshire.
No missed calls going to voicemail that nobody checks. No customers hanging up and calling your competitor instead. Your business stays reachable, but your personal time stays yours.
What Are the Alternatives to BT One Phone?
Broadly, you have three options, and it's worth being honest about all of them.
BT Cloud Voice is the route BT suggests. It's a full office phone system: good if you have a team, desks and a receptionist, but heavy for a one-person business, and it means committing to another contract.
A second handset or a dual-SIM phone recreates what One Phone did, but by hand. You're back to two numbers to manage, and if the business number needs to be a landline, a SIM can't give you one.
A virtual landline puts your business landline number on the mobile you already carry. Nothing new to buy, nothing to install, and the number stays yours. That's what Solofone is, with WhatsApp Business and out-of-hours answering included. For a small business choosing between the three, the question is simply how much system you actually need.
Will the 2027 Landline Switch Off Affect Your Replacement?
No. A virtual landline number already lives on the digital network, so the copper switch-off that Ofcom explains here (completing by 31 January 2027) doesn't touch it. In fact it solves the problem early: instead of waiting for your provider to move your old line, you move the number once and you're done. If your business number still sits on an old BT line, you can port it across and keep it.
Why This Beats BT One Phone
BT One Phone solves the switch off problem by giving you another phone to carry. Solofone solves it by using the phone you've already got.
- No extra device: one phone, one thing to charge
- No extra contract: no second line to manage or pay for separately
- Instant separation: work calls and personal calls are clearly split, without physically splitting your phones
- Never miss a customer: calls outside your hours get answered, not ignored
BT One Phone is a trademark of BT Group plc. Solofone is not affiliated with or endorsed by BT Group.
If you're searching for a BT One Phone alternative because the idea of carrying a second phone doesn't sit right with you, this is built for exactly that.
Get a Small Business Phone Number Without the Second Phone
The landline switch off is happening whether you're ready or not. The only question is what you replace your old line with: a second device you have to carry, or a smarter number that works on the phone you already own.
Solofone gives UK small businesses a proper landline number, WhatsApp Business on the same number, and a receptionist for the hours you're not available, all without you buying, charging, or carrying anything new.
Ready to keep work and personal separate without a second phone? See how Solofone works.