A card combining an Oyster travelcard with credit and cashless payment facilities is being launched.
Barclaycard has secured exclusive rights to use Oyster
The Barclaycard OnePulse can be used to pay for items costing less than £10 without using a Pin number or signing for purchases.
The idea is inspired by the Oyster payment method adopted by Transport for London, in which commuters press a small card against a special pad.
The card was unveiled at an official launch in Canary Wharf, east London.
The bank has struck a deal to try out the new cards and contactless readers with TranSys, the company that runs the Oyster card system with Transport for London (TfL).
The deal gives it the exclusive right, for three years, to put Oyster cards on its Barclaycard credit cards and Barclays Connect debit cards.
The company has stressed, however, that the two types of transaction will remain separate.
For transactions over £10, the OnePulse will require a Pin number or signature for authorisation.
Barclays said if a card is lost or stolen, the cardholder can cancel it and it will no longer work for contactless transactions.
In response to criticism that combining credit card transactions with travel fares could land people in unexpected debt, Sashi Verma, of TfL, said: "People are not incurring any further debt for the Oyster functionality in the card.
"This is for the banking industry to deal with rather than us."
Libby Chambers, of Barclaycard, said: "It is easy to spend, and we make it easy to use by having it available at lots and lots of merchants and locations.
"But we also encourage people to be very responsible, just as we do with the rest of our credit card products."