The Big PSTN Switch-Off: Extended to 2027


BT Group reported last week that the switch-off date for ISDN and PSTN services has been extended to 31st January 2027. This delay offers additional time for businesses and consumers, especially those who are vulnerable, to transition smoothly to more advanced IP-based systems.

For over a century, phone calls in the UK have been handled by the Public Switched Telephone Network (PSTN). This is the umbrella term for the complex infrastructure of telephone lines, satellite links, and switching centres which connect one caller to another when a specific phone number is entered.

Internet calls, video conferencing, and online collaborative tools have far exceeded the capabilities of PSTN, and it is becoming increasingly difficult to maintain. In 2027, the PSTN will be switched off across the United Kingdom, ushering in a new era of telecoms. Digital services will take their place, namely Internet Protocol (IP) or Voice over Internet Protocol (VoIP) phone systems, through which users can make calls via broadband or mobile data.


Why act now?

We are already supporting you to make the switch, migrating your customers onto modern IP phone systems that run on fibre instead of the outdated copper wires that PSTN uses.

Most businesses pay for both phone service and internet access – switching to IP calling brings both under the same roof for lower overall cost and a host of other benefits, including high-quality video conferencing and improved accessibility.

Openreach is dedicated to this hard deadline and has been preparing for the switch-off since 2016. In the public sector, many systems including rail and motorway infrastructure, will need to be updated to function after the PSTN switch-off, and this work is underway. However, the private sector needs to take the initiative to adopt IP services now instead of down the line.

2027 may feel like it’s a way off in the future, but in reality, it’s under three years away. This is why businesses that have not already switched to IP telephony or VoIP must start on it now; the sooner your customer’s adopt the new technology, the sooner their business can benefit from IP calls.


How can my customers prepare?

Businesses that don’t adopt cloud phone systems before the PSTN switch-off will face more problems than just being unable to make calls. Many alarm systems are also connected to a company’s phone lines. If these are still operating on legacy hardware by the time the switch-off comes, they will be rendered inoperable.

Also, lift alarms and other points of contact in an emergency often run on PSTN and must be upgraded before 2027.

Communication providers are aware of how many organisations use PSTN lines but control over the hardware that will need to be swapped out or updated before the deadline is in the hands of those customers. So, the better stock a company takes in advance, the easier its IP transformation will be.

For some small businesses, this may mean buying new dedicated handsets and IT personnel familiarising themselves with their phone service dashboard.

On the other hand, larger businesses may need to retire large amounts of outdated equipment and draw up strategies for new opportunities offered by IP including call analytics and customisable hold messages. This will require extensive planning, so should be completed sooner rather than later to prevent a stressful and costly transformation closer to the deadline.


How can my customers adopt these services by 2027?

We are ready to help Partners make the transition as smoothly as possible, whether it involves swapping old handsets for new ones all at once, or through a phased approach that sees critical systems retired and upgraded one by one.

Once a business has adopted IP telephony, it only pays for what it needs and can easily scale its systems up or down at any time. Between now and 2027, a company may rapidly expand, move location, or enter a new market and seek stats on how its new customers respond to its calls. On a legacy phone system, this would mean added hardware and maintenance costs, limitations on where it can move, and complicated oversight to draw statistical insight from calls.

Adopting IP calling is part of the wider digital transformation that businesses around the country are undergoing. Like the most intense period of the pandemic saw widespread digital transformation, in the adoption of hybrid work suites and cloud collaboration software by many businesses, the time between now and 2027 will be a crucial proving ground for the continued operations of all companies.

We have updated our All-IP Toolkit to help you transition your customers. This can be found here.

If you would like more information on our solutions or have any questions, please don’t hesitate to contact your Partner Business Manager or email us at