Southeastern has admitted advertising out-of-date punctuality information after detective work by a commuter.

Passenger Phil Rogers, co-founder of the Dartford Rail Travellers’ Association (DRTA), noticed that the performance data published on a station poster was strikingly similar to the previous month’s.

Rail-users rely on public performance measurements (PPM) stats to see how their line is performing.

Having been told however that the data was independently verified and that Southeastern was satisfied they were accurate, Mr Rogers carried out his own further analysis.

He noted how "mathematically improbable" it was that the results for each line of route could be the same for two periods in a row, while also reporting that the overall PPM average was 1.3% lower than the previous period.

It is a requirement of both the Southeastern franchise and Southeastern’s own Passenger Charter to provide PPM data by line of route, and overall, for each four-week period. This data is to be provided online and at selected stations.

"Continually lying to customers with wrong data is not what a train company should be doing" - Phil Rogers

The train operator has now accepted that it was a mistake.

"Unfortunately, the wrong poster with the previous month’s data was sent out to stations to be displayed. As soon as this was identified, the posters were removed and the correct ones were displayed," a spokesman said.

The DRTA has now called for an urgent review of its reporting process, and any independent verification, to ensure information provided to customers is accurate and delivered in a "timely manner".

Mr Rogers said it was unacceptable that they continue to fob off passengers and rail-user groups.

"This information is available to them and continually lying to customers with wrong data is not what a train company, that paid a dividend of £25m to their parent company last week, should be doing."

A think-tank report has also called on all rail services in south London, including Southeastern, to be taken over by Transport for London.

Released by Centre for London, it outlines an ambitious package of upgrades which would convert already “strained” services into a high-frequency one modelled on the London Overground.