When customers asked to buy one of the tickets with cash, the Selbys would sell them ones they had already purchased. They stole more than £4,000 on the Liverpool Street to Stansted Airport line before a passenger raised the alarm after Alan Selby sold him a ticket dated seven months earlier. The pair, who also took money from commuters who had to pay a penalty fare, pleaded guilty at Southwark crown court and will be sentenced later.