Legal Firms: Business Continuity and the PSTN Switch-Off

Compliance starts with connectivity

For a law firm, uninterrupted client contact is not a convenience, it is part of how the firm operates. Client instructions and time-critical correspondence all depend on a phone line that works every time it is needed.

The UK’s old phone network, the PSTN, is being switched off completely on 31 January 2027. After that date, anything still relying on the old copper lines stops working entirely. For most businesses, that means an admin task. For a law firm, an unplanned outage is a continuity failure with implications beyond a single missed call.

A firm that hasn’t moved to a digital line before the deadline is exposed to that risk at a time it cannot control.

Why continuity matters for legal firms specifically

Every business depends on its phone line. For legal firms, the stakes carry a professional dimension as well as a commercial one:

• Client instructions are often time-sensitive, particularly around completions and other fixed deadlines. A missed call at one of those moments can affect a live matter, not just a piece of new business.

• Clients share confidential and often sensitive information, and expect the firm to be reachable when it matters. An unplanned outage risks more than inconvenience. It risks the trust the relationship depends on.

• Business continuity is an explicit expectation for regulated firms, not an optional extra. A phone line failure sits squarely within that responsibility.

Firms with employees often run direct-dial extensions alongside a main switchboard number. Each of these depends on the same underlying network, so a switch-off that isn’t planned properly can affect more than one point of contact at once.

What happens when the network switches off

From 31 January 2027, the old copper PSTN and ISDN network stops carrying calls entirely. Openreach stopped selling new copper lines in September 2023, and providers across the UK, including TTNC, have been migrating customers ever since.

Some services move across automatically. Many don’t. Whether a firm’s main line, direct-dial extensions for individual employees, or reception lines carry over cleanly depends entirely on whether a proper migration has taken place before the deadline, not after it.

What a well-managed migration looks like

Moving away from PSTN doesn’t have to disrupt client service, and it doesn’t need to happen at the last minute. Done properly, a migration looks like this:

• Every number the firm currently uses, including direct lines for individual staff, is kept and carried across, with no gap in service.

• Calls follow the right person rather than a single switchboard line, whether someone is in the office, working from home, or at court.

• The move happens on a day and time chosen by the firm, worked around case deadlines and court schedules rather than the provider’s convenience.

• A clear timeline is set out before work begins, so the firm can plan the migration around its own caseload.

The cost of leaving it late

Early movers migrate on their own schedule, with full choice of provider and support availability. Firms that wait until the final months compete for installation slots with everyone else who has also left it late, often when prices and availability are under more pressure.

For firms with several employees and direct-dial lines, migrating each in turn takes longer than a single-line move, which makes early planning more valuable, not less.

How TTNC helps legal firms get this right

TTNC manages this kind of migration end to end, with a UK-based support team and a named contact for each firm throughout.

This applies equally to sole practitioners and firms with multiple partners and employees. Each is migrated under the same process, with every current number retained.

TTNC handles:

• Every number currently in use, ported across with no gaps in service.

• A migration date built around the firm’s calendar and case commitments.

• One point of contact throughout, rather than a call centre queue.

• Clear, upfront terms with nothing added later.

The 2027 deadline is fixed. Early movers avoid the rush and secure current offer terms.

Book your free Switch-Off Ready assessment and arrange this before it becomes a continuity risk.