The PSTN switch-off: what UK retailers must prepare for before 2027

The UK's telephone infrastructure is undergoing its most significant transformation in decades.

Every home and business landline connected to the old Public Switched Telephone Network (PSTN) must transition to internet-based calling by January 2027 - and retail operators face operational, financial, and customer service implications that warrant immediate attention. The deadline is fixed, the preparation window is narrowing, and the businesses that act early will have considerably more options than those that leave it late.

Retail operations rely on landlines more than many sectors recognise. Customer facing contact numbers, back-of-house store communications, alarm systems, payment terminals, and EPoS infrastructure all draw on the copper network in ways that are easy to overlook until a transition is already underway. When the PSTN goes offline, every one of those systems will need a tested, reliable alternative in place.

The Scale of Change Affecting Retail Sites

Openreach has been gradually stopping the sale of PSTN and ISDN products since 2023, with a full switch-off scheduled by January 2027. This affects every retail site in the UK still operating on copper-wire connections, which covers the vast majority of existing store estates. The transition is mandatory, and no exemptions are anticipated for any sector.

Smaller independent retailers and franchise operations face the same deadline as large national chains. Leaving planning until the final months of 2026 risks service disruption at one of the busiest periods in the retail calendar - a risk no operator should willingly accept.

Large retail groups with hundreds of sites face a significant project management challenge, since each location may have different legacy systems, broadband infrastructure, and telephony setups. An organised, site-by-site audit is the sensible starting point before any procurement decisions are made, and the sooner that process begins, the more options remain on the table.

What the Transition Means for Customer Facing Communications

Retail businesses that handle inbound enquiries, complaints, and sales calls through landline numbers need to ensure those numbers remain active and correctly routed throughout any transition period. Losing a well-established customer contact number - even temporarily - carries genuine commercial risk, and the number-porting process requires careful advance planning to avoid gaps in service.

Internet-based calling services offer considerably more flexibility than traditional landlines. A digital voice phone used at store level can route calls to staff on the shop floor, in the stockroom, or working remotely — a capability the old copper infrastructure could not provide. Features such as call routing, voicemail-to-email, call recording, and the ability to receive calls through mobile apps all come as standard with most internet telephony providers.

Call analytics are worth highlighting separately for retail operations managers. Visibility into call volumes, peak contact periods, and missed call rates provides data that directly informs staffing decisions. These are not features that were widely available with PSTN systems, and they represent a meaningful operational improvement once the transition is complete.

Security and Fraud Risks During the Switchover Period

The shift to internet-based telephony carries security implications that retail IT teams should not underestimate. Scammers are actively exploiting the uncertainty of the transition period to target businesses and their customers, with phishing calls impersonating utility providers, telecoms companies, and financial institutions growing more sophisticated. Retail head offices and flagship stores in sectors such as luxury goods, electronics, and financial retail can be particularly attractive targets.

Staff training is part of the response, but selecting a telephony provider that includes built-in call screening and scam number blocking as a standard feature - rather than an optional extra - matters equally. This applies to business accounts and to the residential lines of employees who may handle work-related calls at home.

On the consumer side, households and smaller businesses choosing to upgrade to digital voice through a specialist provider such as Phonely gain access to built-in scam number blocking and real-time call checking against a database of reported fraudulent numbers. That protection activates before a call even connects, which removes the burden of individual judgement at the point of answering.

Equipment and Infrastructure Planning

Many retail businesses assume the PSTN transition requires entirely new hardware across every site. That is not always the case. Analogue handsets can often be retained using a VoIP adapter, which connects between the broadband router and the existing telephone. This option is particularly relevant for smaller sites or retailers looking to manage transition costs without compromising on call quality.

A digital voice phone can plug directly into a broadband router where a new handset is preferred, removing the need for a separate adapter entirely. These devices have become increasingly affordable and are widely available through business telecoms suppliers. Multi-site retail businesses that standardise on a single handset model across their estate simplify support processes and reduce long-term maintenance costs.

Broadband quality is a practical constraint that needs assessing before any site switches over. Most internet telephony services require a stable connection with sufficient upload speed to maintain consistent call clarity. Retail locations in areas with limited fibre coverage may need to address connectivity separately before making the telephony switch. Identifying these issues now avoids the risk of degraded call quality affecting customer interactions once the copper infrastructure is no longer available as a fallback.

Managing the Timeline Effectively

Beginning this process in 2026 rather than now leaves less room to address complications as they arise. Telecommunications providers are already reporting a significant rise in demand for switchover support, and lead times for equipment installation and number porting can stretch well beyond initial estimates once demand peaks. Early movers will have more supplier choice, better pricing leverage, and more time to resolve issues before the deadline.

A structured approach treats the switch-off as a phased project: audit existing systems, map dependencies such as alarm lines, card terminals, and dedicated fax or data lines, test internet telephony alternatives at pilot sites, and then roll out across the estate with enough time to address anything unexpected. Retail businesses with large store portfolios or complex legacy setups should consider engaging a specialist telecoms consultant at the outset rather than partway through.

The Bottom Line

The move away from copper-based telephony will happen on a fixed schedule regardless of where individual businesses are in their planning. Retail operations teams that approach this as a structured infrastructure project - methodically audited, properly resourced, and actioned with enough lead time - will navigate the transition without significant disruption.

Those that leave it late will find tighter timescales, fewer options, and a much smaller margin for error. The 2027 deadline is not moving; the time to act is now.