If you have been hearing about The Big Switch Off and wondering what it means, how it will affect your business or even where to begin, you are not alone. Thousands of UK organisations are still unsure what they need to do and when. With major deadlines now confirmed, it is more important than ever to understand what is changing and how to prepare.
This guide brings you fully up to date and gives you the practical steps you need to navigate the switch from analogue PSTN lines to a fully digital network.
What is The Big Switch Off?
In simple terms, BT Openreach is retiring the Public Switched Telephone Network (PSTN) and ISDN. These traditional copper-based phone lines have powered UK telephony for decades, but the infrastructure is now outdated, costly to maintain and unable to meet modern digital demands.
As part of the transition, all PSTN and ISDN services will stop working and be replaced by digital alternatives such as VoIP (Voice over Internet Protocol) delivered over fibre broadband. This affects thousands of businesses and covers far more than just phone lines, including:
- Landline telephone systems and on-premise PBX solutions
- ADSL and FTTC broadband connections
- Security and fire alarm systems
- Payment terminals, Chip & PIN and EPOS devices
- Lift and emergency communication lines
- Fax and legacy analogue equipment
When is The Big Switch Off happening?
The process is already underway. In September 2023, Openreach introduced a nationwide stop-sell, meaning no new PSTN-based services can be purchased or modified. Existing services still operate today, but every analogue line must be migrated before the final switch off deadline.
The PSTN will be fully retired on 31 January 2027. After this date, any service still running on PSTN or ISDN will cease to function.
Key dates you need to know
- 5 September 2023: National stop-sell on new PSTN, ISDN and WLR services. Customers must choose digital alternatives.
- By end of 2025: Openreach aims for the majority of customers to have migrated away from PSTN-dependent services.
- 31 January 2027: Full shutdown of PSTN and ISDN networks. All remaining analogue services will stop working.
- 2030s: Through Project Gigabit, the UK is working towards gigabit-capable broadband for nearly all premises to support long-term digital communication.
Who will The Big Switch Off affect?
The short answer is: everyone still relying on analogue lines. While many households and organisations have already moved to digital services, thousands of businesses still use PSTN without realising it. Even if your phone system is modern, connected equipment such as alarms, lifts or payment terminals may still rely on analogue lines in the background.
Globally, many countries have already completed their analogue switch off, and the UK will soon follow.
What does The Big Switch Off mean for your business?
Once PSTN and ISDN services shut down, any device or system still connected to them will immediately stop working. This may include:
- Phone systems and call routing
- Intruder and fire alarms
- EPOS and payment terminals
- Door entry and access control
- Lift emergency phones
- CCTV systems using copper-based connectivity
Awareness remains low. Industry research shows that almost half of UK organisations were unaware of the Big Switch Off as recently as 2021, and many remain unprepared today. BT encourages businesses to begin migrating early, rather than risking last-minute disruption.
What do you need to do?
To make your transition smooth and stress-free, here are the essential steps every business should follow:
1. Audit your PSTN lines and connected devices
Start by identifying exactly what in your organisation still relies on PSTN or ISDN. This includes voice and non-voice devices. Moneypenny clients can access a FREE digital transformation audit via our partner, Lily Comms. Submit your details here to get started.
2. Research digital alternatives
From cloud telephony to fibre broadband and VoIP systems, you will need new solutions to replace your analogue services. If you choose Lily Comms’ free audit, you will receive personalised recommendations and clarity on what technology is available in your area.
3. Contact suppliers early
Demand for engineers, hardware and migration support will rise as 2027 approaches. Begin conversations now to avoid delays and ensure you secure the right solution at the right time.
4. Check your equipment capability
Many organisations discover that older handsets, routers or alarm panels are not compatible with VoIP or digital services. Review your existing hardware to understand what can stay, what needs updating and what requires replacement.
5. Start your migration plan
Work with your chosen provider to create a detailed, phased migration plan. If you are a Moneypenny client, ensure you include resetting your divert number so your calls continue to route correctly during and after the transition.
Want even more guidance?
For a deeper look at timelines, risks and preparation steps, explore our full PSTN checklist guide: The PSTN Switch Off Checklist.
Get expert help with Moneypenny
If you need support, have questions or want help resetting your Moneypenny divert number, our Client Support Team is always here for you. Call us on 0345 123 3700.
For even more guidance, you may also find our detailed article helpful: ISDN Switch Off: The Top Questions Answered.
