If you use a Pop pay-as-you-go card on the Northumberland Line, there is a reasonable chance you are being overcharged, and a very good chance you do not know about it. This is not speculation. It is documented in Nexus’s own data, and the Rail Ombudsman has formally described it as an ongoing and systemic issue. The fault has been known to Nexus since January. It has not been fixed.

This piece is to explain what is happening, why most affected passengers will not have noticed, and what you can do if you think you are one of them.

What’s actually happening

The Pop card system has a published daily cap. In zones A to C, the cap was £5.20 before 1 April 2026 and £5 after. If you tap on and off normally, you should never be charged more than that in a single day, no matter how many journeys you make.

On the Northumberland Line, this isn’t what’s happening. The system is charging passengers above the cap, sometimes by 20 pence, sometimes by several pounds. In my own case, I have been charged £9.80, £12.70, and £13.60 in a single day, against a £5.20 cap. The data showing this was sent to me by Nexus’s own complaints team. Their internal notes attribute every overcharge to system faults, not user error.

Why most people won’t have noticed

The Pop card overcharging is invisible to most people who experience it, and that is the most important thing to understand.

There is no online portal that lets a Pop PAYG user audit their own charges. You cannot log in and check what you were charged on Tuesday last week. The Pop app itself does not reliably show top-ups; my own bank records show top-ups that the app does not display. The only way to detect an overcharge is to compare your bank statement against your travel pattern, day by day, and most people have no reason to do that. If you need to top up again sooner than you expected, the natural assumption is that you have travelled more than you remember. The system is designed to hide its own faults, and when I requested information about my travel, I was told Nexus had lost that data; they only found it again after I took them to court.

The other reason this has gone unnoticed is the user mix. A large proportion of regular passengers on the Northumberland Line use rail passes, season tickets, or other ticketing products that aren’t affected by the Pop daily-cap fault. Those passengers are travelling the same routes as the rest of us and seeing no problems, because the problem doesn’t affect how they pay. If you have a pass, this isn’t happening to you. If you tap on with Pop PAYG, it almost certainly is.

What I’ve tried, and what’s happened

I reported the overcharging to Nexus in January. The response, over the months that followed, has been a pattern of partial answers, missed commitments, and eventually a refusal to engage substantively while my case was in the formal channels. I sent a Letter Before Action in March. I filed a money claim in the small claims court in May. Nexus failed to respond to the court until the final hours of the deadline, and then only by email to a generic inbox rather than through the proper online court system, further delaying the case.

In parallel, I have approached everyone who, in principle, should be able to act. The Rail Ombudsman declined jurisdiction on the basis that the issue is systemic. Transport Focus, the passenger watchdog, closed my case because Nexus would not engage with them while my claim was active. My MP, Ian Lavery, has been given the same line. NECA, the Combined Authority that oversees Nexus, has acknowledged my complaint but not answered it. A complaint to the Competition and Markets Authority has been submitted. None of this has fixed the underlying fault.

The fault continues. It is overcharging me, and on the ombudsman’s own reading, it is overcharging every other Pop card user on the line. Every day.

What to do if you think you are affected

If you use Pop PAYG on the Northumberland Line, the practical steps are straightforward and worth doing even if you are not sure.

Check your bank statements from the last few months for Nexus top-up transactions. Compare the total spend in a single day against the daily cap. If you spent more than £5.20 in a day before 1 April, or more than £5 after, on Pop card top-ups, you have been overcharged. The amount may be small in a single day, but across weeks and months, it adds up.

Take screenshots or record anything that looks wrong, with dates. Bank statements, Pop app screens, ticket gate emails, if you have them.

Contact Nexus customer relations and ask them to send you a transaction history for your Pop card covering the period you are concerned about. Send the request in writing, by email, so you have a record. Reference the daily cap and your concern that charges exceeded it.

If Nexus’s response is unsatisfactory, you have escalation routes. Transport Focus accepts passenger complaints and aggregates them, which is important for evidencing a systemic issue. The Information Commissioner’s Office handles data access failures if Nexus does not provide the transaction data you request. The Money Claims service at gov.uk allows you to file a small claims court claim to recover overcharges, and the process is designed to be navigable without a solicitor.

And, if you would, get in touch. I am keeping a record of affected passengers because the strength of every other route, including any future regulatory action, depends on showing that this is not one person’s complaint but a pattern. Your details would not be shared without your permission, and you would not be committing to anything by getting in touch. The point is simply to build a picture of how many people are affected, on which days, in what amounts.

Why this matters beyond the money

In my own case, the overcharging has so far cost me hundreds of pounds in under a year. For other regular Pop PAYG users on the line, the picture will be similar. The amount on any single day is small enough to overlook, sometimes only 20 pence, sometimes a few pounds, and that is exactly what makes the fault so insidious. Stacked over weeks and months of regular travel, those daily increments add up to significant sums. Occasional users may have lost less; people who use the line for the school run, for commuting, or for daily travel will likely have lost considerably more than they realise.

That is, in effect, the calculation the operator is making. A publicly-owned transport body is operating a charging system it knows to be faulty, and has chosen to leave it operating for at least five months, because no single day’s overcharge is large enough for any individual passenger to make a fuss about, and the wider class of affected passengers has no way of knowing they are in it. The accumulated loss across all affected passengers is substantial. The political and reputational cost to the operator of leaving the fault in place is, on the evidence so far, less than the cost of fixing it.

That calculation only works if it goes uncontested. The way it gets contested is for affected passengers to notice, to document, and to come forward. Each individual case feels small. The pattern is not, and the totals genuinely are not.

Check your statements. Get in touch if you find something. It costs you nothing, and it changes the picture.