Tens of thousands of students in the capital are unable to renew their Oyster cards thanks to the postal strikes.
Bus drivers are being told to accept the expired student Oyster cards as millions of postal items pile up in Royal Mail warehouses – including renewed Oyster cards.
Full and part time students over the age of 16 are eligible for discounts or free travel on buses and trams.
But when they expired at the end of September, the renewed Oyster cards hadn't come through.
The Transport for London says it cannot automatically renew cards, which would mean students face paying £3 for a new one plus the pay-as-you-go fares – or the £2 standard fare for each bus journey.
The TfL says the strikes are out of their hands but they are working hard to give out refunds.