A BBC investigation has found that forged rail tickets are being sold online and can be used without detection.
The corporation said it had bought counterfeit tickets on the ‘dark web’, using the virtual currency Bitcoin.
'There's something on there that shouldn't be on there'
It bought a first class fare from Hastings to Manchester, and a monthly ticket between Gatwick and London for significantly less than the full price and said it had used them without problems.
The online seller said the magnetic strips on the paper tickets would not work but rail staff would still let passengers through the barriers.
The fraudsters, whom the BBC did not name, said in a statement: ‘The train companies keep stuffing their pockets with public subsidies while treating the operation of rail services as an inconvenience.
‘No-one should be ashamed of getting one over companies like Southern Rail. We wish one day everyone will be able to use an affordable public service. Until then, we will be providing it.’
In fact, under its unique contract, Govia Thameslink Railway, which runs Southern, hands all revenues over to the Department for Transport.
Rail fraud investigator Mike Keeber told the BBC that the fake tickets were very convincing, but ‘there's something on there that shouldn't be on there’.
He added: ‘I'd rather not say what it is, as people who make this [could] change it and make our lives harder.’