"The Oyster card has great benefits to Lewisham's travelling public and will be even more useful when it is accepted by the train companies operating railway stations locally," according to Liberal Democrat Cllr Chris Maines. "However, the fact that personal and travel details can be accessed by the Police seems to be a hidden feature of the card."

It is believed that the Home Office has also made discreet inquiries to discover what further information can be added and accessed to the card. The issue has been exposed by Channel 4 and is being raised in Parliament by Liberal Democrat MP Lynne Featherstone.

Blackheath councillor Chris Maines says, "The public are encouraged to purchase and register the Oyster pay-as-go card as there are many advantages, not least that fares for card users have been frozen for next year. What concerns me is the secretive manner in which these 'Big Brother' tactics are adopted."

A recent Freedom of Information request has recently revealed that police monitoring of Oyster cards has increased by 300% in a year.

"I accept there may be valid reasons for the police to request this information and a valid outcome," says Cllr Maines, "but why the secrecy? Our capital has a huge number of surveillance cameras but there are protocols regarding their use and there are signs warning the public that they are being filmed. We are not told when purchasing an Oyster card that data and information is passed on to other agencies in this way."