Pay By Touch, which is in use at 2,000 stores in the US, doesn't use actual fingerprints, but instead takes tiny measurements from the finger. Because these are unique to the individual, only he or she can access their bank account information.
But it was the search for an effective means of age verification that led Midcounties Co-op to Pay By Touch. Retail chief operating officer Bill Laird says: "We were one of the pioneers of self-checkouts but we discovered that verification of age was slowing down transactions, so we started to think about what we could do for the students in Oxford to save them having to bring ID with them every time.
"We found out about biometric identity, where you register information on a fingerprint, and thought it was a great idea. Then I read about Pay By Touch as a method of payment and it made absolute sense. I went to the US to see it being used and was taken by how easy it was."
Shoppers can sign up online or at the registration kiosk at one of the three stores - in Carterton, Headington and Summertown. All that's needed is a photocard driving licence or passport, and a bank account.
To activate the account, the customer must show a member of staff a printout of the authorisation mandate form issued at the end of the sign up, plus a copy of a bank account statement, the Pay By Touch search number which shoppers choose during the sign up, and a photocard driving licence or passport. The employee then scans the customer's index finger on both hands.
Once the bank has approved the direct debit account, the Pay By Touch system is ready to use.
"This is not instead of Chip and PIN; it enhances it," says Laird. "Some people are nervous about Chip and PIN and this negates all of that. It's something everyone can use, no matter what their age. It also leverages the investment we've made in Chip and PIN. Plus, if a customer likes what we're doing, it gives us a competitive edge. The process is also cheaper than credit card transactions because it's a direct debit.
"The Co-op stands for giving people choice and this gives them another choice of payment," adds Laird. "But the best bit is it's not Tesco who did it. It goes to show that some of the smaller guys can be just as clever as the big guys.
"If the feedback is positive, we have three more stores lined up to run the system - one in Swindon and two in Gloucester. Then we'll stand back and measure the reaction in all six. If people like it, we'll consider a rollout to all 152 stores."
Abi Ward from Headington, Oxford
"I usually carry a massive bag and have a huge purse with loads of receipts and cards in it, so Pay By Touch is really handy. It actually felt quite liberating. I've come and bought my shopping but that's all I've got in my hands
- I don't have to hunt around for my purse.
I've got a cash card - I don't have credit or debit cards - but nobody needs to know that so it feels very democratic. Ultimately, if someone sees me putting my PIN number in they can't do much about it without my fingerprint. I hope it catches on in other places."