PSTN switch-off timeline — key dates

PSTN Switch-Off Timeline: Key Dates for UK Businesses

The dates that matter, what each milestone means, and when UK businesses should act

The PSTN switch-off is not a one-day event. It is a planning window with key milestones that affect line audits, dependent services, migration timing, and business continuity. Use this page to understand the major dates, the practical planning windows around them, and the action points you should not leave until the last minute.

PSTN switch-off hubBusiness checklistMigration guide

Strategic planning graphic for the UK PSTN switch-off in 2027, featuring readiness routing and business continuity safeguards for VoIP migration.

Final network target

31 January 2027 is the retirement target for the analogue PSTN / WLR network, but most businesses should be planning and moving well before then.

The major dates at a glance

This page is about timing, planning windows, and deadlines. It does not compare providers and it does not replace the checklist or migration guide.

September 2023: analogue stop-sell already in place
End of December 2025: BT Business action point for moving early
31 January 2027: final analogue PSTN / WLR retirement target

PSTN switch-off hubMigration guide

September 2023

Analogue stop-sell

New analogue phone lines stopped being sold to new customers. Legacy estates should now be treated as transition estates, not permanent setups.

End of December 2025

Move-early milestone

BT Business urges business customers to move by the end of 2025, giving time for audits, porting, testing, and controlled change before the final network target.

31 January 2027

Final retirement target

Any remaining services that still depend on PSTN / WLR-era infrastructure need a managed exit plan before this point, especially where continuity-critical systems are involved.

PSTN switch-off timeline: what changes, what it means, and what to do

This section keeps the timeline separate from provider choice. Use it to understand planning windows, dependency pressure, and why the final deadline should not be treated as the starting point for action.

PSTN timeline for UK business planning

Use this timeline to separate the national dates from the practical planning windows your business should work to.

Date / window

What changed

What it means for businesses

What to do

September 2023

Analogue stop-sell in place. New analogue phone lines stopped being sold to new customers, which means the market is already in transition rather than waiting for 2027.

Legacy line estates should now be treated as temporary operating environments. New provisioning assumptions have changed, even where older services are still live.

Audit existing lines, numbers, sites, and connected services. Stop treating older analogue dependencies as “business as usual”.

2024 to 2025

Readiness and remediation window. This is the right period for identifying dependent services, assigning owners, and designing the migration path.

This is where most avoidable problems are either prevented or created. Delayed audits usually lead to late discovery of alarms, lift lines, door entry, fax, CCTV, EPOS, or broadband dependencies.

Run a business checklist, document dependencies by site, confirm contracts, and decide whether the migration should be phased or handled in a single cutover.

End of December 2025

BT Business move-early milestone. BT Business urges business customers to move by the end of 2025 rather than waiting for the final 2027 retirement target.

This is the practical action point for many organisations. It leaves room for number planning, device changes, testing, and continuity review.

Have the migration path confirmed, porting expectations understood, and internal cutover owners in place before this point.

2026

Execution and control window. This is when slower organisations are likely to be carrying out live change, remediation, and fallback planning.

Leaving execution to 2026 reduces comfort margin. Multi-site businesses and organisations with dependent systems are more exposed if planning is still incomplete at this stage.

Complete testing, confirm fallback call routes, finalise number treatment, and check continuity-critical services before go-live.

31 January 2027

Final analogue PSTN / WLR retirement target. Legacy services that still depend on the old network need to be moved, replaced, or otherwise handled before this deadline.

Any unresolved dependencies become business continuity risks. Some services may be moved through protective programmes, but others cannot be relied on to transition automatically.

Be fully off unsupported analogue dependencies before this point. Do not leave critical services exposed to a last-minute response model.

The timeline matters because PSTN switch-off risk is usually operational before it becomes technical. The biggest problems tend to be late discovery of dependencies, weak testing, unclear ownership, and avoidable continuity gaps during change.

What each milestone really means

Most businesses do not fail because they misunderstand the final date. They fail because they discover the real operational impact too late.

Why September 2023 matters

The national move is already underway. The stop-sell phase means the market stopped treating analogue services as the future some time ago, even if many older lines remain live.

Planning the move from PSTN to VoIP for UK businesses.

Why the end of 2025 matters

For many businesses, this is the real action deadline. It gives enough time for audits, internal approvals, number work, testing, and fallback planning before pressure becomes harder to control.

Continuity and operational control during PSTN migration.

Why 31 January 2027 matters

This is the final network target, not the ideal starting point. Businesses still carrying unresolved dependencies into 2026 and 2027 are more likely to be dealing with avoidable continuity risk.

Reminder milestones for business planning

You do not need to treat every milestone the same way. Use the current stage you are in to decide the right next action.

Now: audit lines, numbers, sites, and line-dependent services
Before end of 2025: confirm the migration path, owners, testing approach, and number handling
During 2026: complete testing, cutover control, fallback routing, and continuity checks
Before 31 January 2027: be fully off unsupported analogue dependencies

Business checklistMigration guideBack to PSTN hub

Detailed timeline and guidance for the UK PSTN to VoIP migration, highlighting routing for business continuity and risk mitigation.

Frequently asked questions

Common questions about PSTN switch-off dates, timing, and what businesses should treat as the real action window.

The national retirement target for the analogue PSTN / WLR-era network is 31 January 2027. That is the final target date, not the ideal point to begin planning.

Because BT Business urges customers to move by the end of December 2025, giving time for audits, testing, number work, and controlled cutovers before the final 2027 target puts more pressure on change activity.

Yes. The analogue stop-sell phase has already been in place since September 2023 for new customers. Many older services remain live, but the transition has been underway for some time.

Look beyond desk phones. Businesses should review alarms, lift lines, door entry, CCTV, fax, EPOS, broadband dependencies, and any continuity-critical service that still depends on an older line environment.

Because this page is about timing and milestones only. The checklist is for auditing and preparation tasks, while the migration guide is for the actual move process. Keeping them separate avoids intent blur and keeps each page useful.

No. Waiting until the final date usually reduces planning flexibility and increases the chance of rushed remediation, weak testing, unclear ownership, or continuity gaps during cutover.

Next step

Use the timeline, then move into action

Once the timing is clear, the next job is practical preparation. Use the checklist to audit dependencies and the migration guide to plan the move in a controlled way.

PSTN business checklistPSTN migration guideBack to PSTN hub