BT has confirmed that the BT PSTN retirement will be complete by January 2027. Any business still running on copper lines after that date will simply lose its telephone service with no warning and no recovery path. The time to plan your migration is now.
What Is the PSTN and Why Is It Being Switched Off?
The PSTN switch off 2027 is one of the most significant changes to UK business communications in a generation. PSTN stands for Public Switched Telephone Network, the traditional copper wire infrastructure that has carried telephone calls across the UK for over a century. It is the technology behind standard landlines, ISDN connections and many broadband services that businesses and homes have relied on for decades.
The problem is straightforward: the PSTN is old. The copper cables that make up the network are expensive to maintain, increasingly unreliable and completely incompatible with the digital communications technology that modern businesses depend on. BT, which operates the UK copper network through its Openreach division, has been warning for years that the infrastructure was approaching the end of its useful life. The BT PSTN retirement is not a surprise announcement. It has been planned since 2020.
Rather than continuing to pour investment into an ageing system, the decision has been made to replace it entirely with Voice over Internet Protocol (VoIP) technology, carrying digital calls over broadband connections instead of copper wire. Ofcom has confirmed the transition and the deadline is set: 31 January 2027. This is not a consultation or a draft proposal. The copper network switch off is happening, and preparation cannot be deferred any longer.
Which Businesses Are Affected by the PSTN Switch Off UK?
The digital phone switch off affects virtually every business that still uses any component of the copper telephone network. If your business uses any of the following, you need to act before the landline switch off 2027 deadline:
- Standard BT landlines (analogue lines) whether for voice calls, fax or broadband
- ISDN2 or ISDN30 connections as part of a traditional PBX phone system. The ISDN switch off 2027 affects every organisation still using these circuits, regardless of size or sector
- ADSL or FTTC broadband delivered over a copper line with a landline component
- Alarm systems, lift phones or door entry systems connected to the copper network
- Card payment terminals or EPOS systems using a phone line connection
- Fax machines connected to a landline
If your business is already using a full fibre (FTTP) broadband connection with a cloud based phone system, you may already be ahead of the curve. However, if you still have any device or service connected to a traditional copper line, you will still need to act. Check with your provider to be certain.
Key Dates and Timeline
Which Devices Stop Working After the PSTN Switch Off?
The PSTN switch off 2027 does not just affect your desk phone. A wide range of devices that businesses use every day rely on the copper network and will stop functioning unless they are replaced or reconfigured before the January 2027 deadline.
This is the most commonly overlooked issue in PSTN migrations. Many business premises have intruder alarms, fire detection systems and lone worker devices that use the PSTN to communicate with monitoring centres. Contact your alarm maintenance company now to arrange a survey and replacement solution well before the deadline.
Your PSTN Switch Off 2027 Migration Checklist
Work through each step below and tick each item off as you complete it. Use this as your internal action plan to make sure nothing is missed before the PSTN switch off 2027 deadline. If you would rather have an expert walk you through it, our team at Blake Telecom will handle everything for you.
PSTN Migration Checklist
Interactive: tick each item as you complete it
What Replaces the PSTN? Understanding VoIP and UCaaS
The PSTN is replaced by Voice over Internet Protocol (VoIP), a technology that carries phone calls as digital data over a broadband connection rather than through a physical copper wire. VoIP has been available for many years and is already the technology behind most modern business phone systems. The VoIP migration 2027 window is closing fast, and if you have not already switched, the time to act is now.
Many businesses go further than a straight like-for-like replacement and opt for a UCaaS and CCaaS platform, which stands for Unified Communications as a Service. This brings your phone calls, video meetings, team messaging, free call recording, and analytics together into one platform on one monthly subscription, rather than managing separate tools that never quite work together. It is the most significant upgrade in business communications most companies will ever make, and the PSTN switch off 2027 deadline is the trigger to make the move.
What you gain by switching to a modern hosted VoIP system
- Make and receive calls from any device, whether a desk phone, laptop or mobile, all using your business number
- Free mobile and desktop apps for your entire team with no additional cost
- HD voice quality on every call with 99.999% uptime backed by an SLA
- Video conferencing, team messaging and file sharing in a single app
- Free call recording included as standard on every plan, with 30 day storage and compliance options available
- Smart call routing, auto attendants and hunt groups without expensive hardware
- Real time dashboards and call analytics for full management visibility
- CRM integrations with Salesforce, HubSpot, Microsoft Teams and 50 plus other platforms
- Scale up or down instantly by adding users without engineer visits or hardware upgrades
Despite initial concerns about the digital phone switch off, the vast majority of businesses that migrate to VoIP report better call quality, lower monthly costs and capabilities they simply did not have before. The PSTN switch off is an opportunity, not just a deadline.
Old vs New: PSTN Compared to Hosted VoIP
The table below gives a clear side by side view of what businesses lose when the copper network switch off happens and what they gain by moving to a modern hosted VoIP or UCaaS platform.
| Feature | Traditional PSTN / ISDN | Hosted VoIP (Blake Telecom) |
|---|---|---|
| Works after January 2027 | ✗ No | ✓ Yes |
| Call quality | Standard definition audio | HD voice on every call |
| Monthly cost | High: line rental plus call charges | From £8.99 per user per month |
| Call recording | ✗ Not included | ✓ Free on every plan |
| Video conferencing | ✗ Not available | ✓ Up to 500 participants |
| Mobile app | ✗ Not available | ✓ Free for all users |
| Remote working support | ✗ Fixed location only | ✓ Work from anywhere |
| Adding new users | Engineer visit required | Done online in minutes |
| Hardware required | Physical PBX on-site | None required |
| CRM integration | ✗ Not available | ✓ 50 plus integrations |
| System updates | Manual and costly | Automatic and included |
| Uptime guarantee | No SLA | 99.999% with financial backing |
Frequently Asked Questions About the PSTN Switch Off 2027
No. Your existing business phone numbers, including local geographic numbers and 0800 numbers, can be ported to your new VoIP system. Blake Telecom manages the entire porting process on your behalf and your numbers are live on the new system before your old lines are cancelled. You will not lose your number.
VoIP calls use a relatively small amount of bandwidth, typically around 100 Kbps per simultaneous call. Most modern broadband connections handle VoIP comfortably. For larger teams or businesses with high call volumes, we recommend a dedicated leased line to guarantee consistent performance. We can assess your current connection as part of a free migration consultation.
Our platform includes automatic failover. If your broadband connection drops, incoming calls are automatically rerouted to your mobile app or a backup number so your business stays reachable. This is managed at the platform level and requires no manual intervention from your team.
Most business migrations with Blake Telecom are completed within 24 hours. If you are going app only with no physical hardware, we can often have you live within two hours of placing your order. We configure everything in advance and handle your number porting, so your team experiences minimal disruption.
This is one of the most important steps to address early in your PSTN switch off 2027 preparation. Contact your alarm or security system maintenance company and confirm whether your system uses the PSTN to communicate with its monitoring centre. If it does, your provider will need to upgrade the communicator unit to a digital alternative before your copper line is removed. Do not leave this until the last minute as alarm providers are already busy with migration work.
Modern hosted VoIP platforms are built on geo redundant cloud infrastructure with uptime SLAs of 99.999%, which equates to less than six minutes of unplanned downtime per year. By comparison, traditional copper lines have no uptime guarantee and are far more vulnerable to physical damage and weather events. In most cases a well configured VoIP system is more reliable than the PSTN it replaces. Ofcom has also published guidance on protecting customers throughout the digital migration process.
VoIP refers specifically to making phone calls over the internet. UCaaS, which stands for Unified Communications as a Service, is a broader platform that includes VoIP calling alongside video conferencing, team messaging, call recording, analytics and CRM integration, all in one subscription. Most businesses find that a UCaaS platform gives them significantly more value for a similar or lower monthly cost than their old PSTN setup. You can explore our full UCaaS and CCaaS solutions here.
Useful Links and Further Reading
The following resources will help you plan your VoIP migration 2027 and understand the regulatory background to the PSTN switch off UK.
