Updated London commuters are suffering more problems than usual this morning, thanks to the weekend failure of the Oyster card readers at tube stations and on buses.
Extra staff have been drafted in this morning to sort out problems with cards which were used between 5.30am and 10.30am on Saturday. Some cards were apparently wiped, meaning some customers were left with cards that didn't work and/or a fine.
Although the problems were supposedly fixed by 10.30am Saturday morning, we've had reports of problems on buses up until late Saturday evening.
Certain Freedom Passes and Young Persons Oyster cards might also need to be exchanged for a new card. Transport for London believes as many as 40,000 cards might have problems.
TfL said the computer problem was fixed at 9.30am on Saturday but some retailers did not get ticket services back until Sunday. People who were charged a maximum fare on Saturday morning will get an automatic refund on Tuesday.
The problem comes just weeks after Dutch researchers found a way to clone the Mifare chip which the card is based on. Chip company NXP is taking legal action to silence the university researchers who revealed the problem.
Update: A TfL spokesperson sent us the following statement:
The vast majority of passengers have travelled without any disruption this morning and London Underground staff have minimised the delay to passengers with cards that are not working.
Less than 1% of the 6 million regular Oyster card users required replacement cards after the incident on Saturday morning. We are replacing affected cards and there are now less than 35,000 cards that need to be replaced. If this has not been practical during this morning, LU staff, and London bus drivers, have allowed these passengers to travel.
Ticket offices are well stocked and we advise those passengers who have not yet replaced their cards to go to their nearest LU ticket office through-out today.