Thirty Years of Number Portability: The Consumer Freedom That Was Quietly Stolen Back

In 1999, the UK became one of the first countries in the world to introduce full mobile number portability — the ability to take your phone number with you when you switch networks. It was, at the time, presented as a landmark moment for British consumers. No more being held hostage by your network simply because you'd given your number to your employer, your doctor, your friends. Competition would flourish. Prices would fall. Networks would have to earn your loyalty rather than simply trap you.

Three decades on, it's worth asking an honest question: how much of that promise actually survived contact with commercial reality?

What Number Portability Was Supposed to Do

The theory was elegant. Before portability, switching networks meant changing your number — a genuinely significant deterrent that network operators exploited ruthlessly. By decoupling your number from your provider, regulators hoped to create a truly competitive market where consumers could vote with their feet, and networks would compete on price, coverage, and service quality.

For a while, it worked reasonably well. The PAC (Porting Authorisation Code) system, while not seamless, gave consumers a mechanism to switch. Ofcom data from the early 2000s showed switching rates climbing steadily as consumers exercised their newfound freedom.

But markets have a way of adapting to rules they find inconvenient.

The Friction Machine

Over the years, networks developed an increasingly sophisticated toolkit for making switching feel harder than it should be. None of these tactics are necessarily illegal. Most are technically compliant with the rules. But taken together, they represent a systematic erosion of the switching freedom that portability was meant to guarantee.

Retention call gauntlets became an art form. Request a PAC code and you'd be transferred to a specialist 'loyalty' team, trained to make you feel guilty, uncertain, or simply exhausted enough to give up. Ofcom did eventually require that PAC codes be provided via text within two hours — a rule introduced in 2019 that genuinely improved the process. But the retention culture around it persists.

Credit check loopholes represent a more troubling issue. When a consumer ports their number to a new network and takes a new contract, the receiving network runs a credit check. This is standard practice. But consumer advocates have documented cases where networks have used marginal credit scores to decline applications from customers attempting to switch away from more expensive legacy contracts — effectively using financial vulnerability as a tool to prevent switching.

The 30-day notice trap remains a live issue for many customers. While Ofcom's rules have improved the PAC process itself, consumers who don't initiate a port before their contract ends can find themselves rolling into expensive monthly rolling tariffs — sometimes for months — before they successfully complete a switch.

Bundled service dependencies have become increasingly common. Networks now routinely bundle mobile contracts with home broadband, streaming services, and device finance agreements. Switching your mobile means unpicking a web of interconnected products, each with its own notice period and early exit penalty. The practical barrier to switching is substantially higher than the PAC code process alone suggests.

The Vulnerable Customer Problem

The impact of these friction points is not evenly distributed. Ofcom's own research consistently shows that older consumers, those on lower incomes, and customers with lower digital literacy are significantly less likely to switch — and significantly more likely to remain on expired contracts paying above-market rates.

For these groups, the credit check issue is particularly sharp. A customer who has been with the same network for a decade, paying their bill reliably every month, may nonetheless fail a credit check when attempting to switch — particularly if they've had financial difficulties at any point in the recent past. The irony is profound: the customers most likely to be on expensive legacy contracts are among those least able to navigate the switching process successfully.

Age UK and Citizens Advice have both raised concerns about this dynamic in submissions to Ofcom over the years. The regulator has acknowledged the problem. Progress in addressing it has been slow.

What Ofcom Has Done — and What It Hasn't

To be fair to Ofcom, the regulator has made genuine improvements to the switching landscape over the past decade. The 2019 PAC code reforms were meaningful. The requirement for networks to send customers a text confirming their PAC code, along with clear information about any outstanding contract obligations, was a real step forward.

The automatic compensation scheme for broadband faults has been extended in scope, and there's been ongoing pressure on networks to improve the transparency of their coverage and pricing claims.

But consumer advocates argue that the pace of reform has consistently lagged behind the pace at which networks develop new retention tactics. Each regulatory intervention addresses a specific behaviour — and networks respond by finding adjacent behaviours that achieve the same commercial objective through technically compliant means.

The credit check issue, in particular, remains largely unaddressed. There's currently no obligation on networks to offer alternative pathways for customers who fail credit checks when switching, no requirement to explain why an application was declined, and no straightforward appeals process.

Is the System Fit for Purpose in 2025?

The honest answer is: partially, and less so than it should be.

For a digitally confident consumer, on a standard single-service mobile contract, with a clean credit history, the current system works tolerably well. The PAC code process is faster than it was. Switching times have reduced. Price comparison is easier than ever.

For a significant minority of British consumers — the elderly, the financially stretched, those with complex multi-service bundles, those in the middle of device finance agreements — the practical experience of switching remains needlessly difficult, and the protections available when things go wrong are inadequate.

There are also emerging challenges that the current framework wasn't designed for. eSIM technology, which is now standard on most flagship handsets, should theoretically make switching almost instantaneous — a genuine revolution in consumer freedom. But the major UK networks have been notably slow to implement seamless eSIM switching, and the technical standards that would enable it remain inconsistently applied across providers.

What Needs to Change

If number portability is to deliver on its original promise in 2025 and beyond, a few things need to happen.

First, Ofcom needs to address the credit check switching barrier directly — either by requiring networks to offer alternative assessment pathways, or by mandating that existing customers with clean payment histories receive preferential treatment when switching.

Second, the bundled service problem needs regulatory attention. As networks increasingly tie mobile contracts to broadband and other products, the effective switching barrier grows — and the rules need to reflect that reality.

Third, eSIM switching standards need to be mandated, not left to commercial negotiation between networks that have a shared interest in keeping the process slow.

Thirty years is long enough to assess whether a regulatory intervention has worked. Mobile number portability was a good idea, imperfectly implemented, and subsequently undermined. The question for the next thirty years is whether the regulator has the appetite to fix it.