Any transaction over £10, however, will still need a Pin to verify it.
Wave and pay
"We are excited about installing cashless readers in 25 of our London stores," said Guy Harvey, financial director at UK High Street sandwich chain Eat.
"It will help us to eliminate some of the frustrations for our customers, such as queues in the busy lunchtime rush."
In addition to making small transactions, the credit card is also designed to act as an Oyster card for travel on London's Tubes and buses.
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.
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.
Security issues
Barclays is confident that the combined credit and Oyster card will be popular, particularly in London.
It says the new cards cannot be cloned or counterfeited and if a card is lost or stolen, the cardholder can cancel the card and it will no longer work for contactless transactions.
But analysts have raised questions about whether security could be compromised and if will lead to a rise in card fraud.
Meanwhile, Visa and Mastercard will also be introducing the touch-and-pay technology in certain London locations in September for their credit cards.
