Tesco is trialling new technology allowing shoppers to pay for products in story without going to the till.
The supermarket giant has given some staff at its headquarters an app for their smartphones which allows them to scan barcodes and pay through their devices.
The experiment eliminates the need to queue at tills, but Tesco said it is in its very early stages.
It added that it fears stores without checkouts could become targets for shoplifters, potentially rendering the technology unviable.
Chief Executive Dave Lewis told the BBC: "If the margin in the business is two or three per cent, you don't have to lose much to make it unprofitable."
It comes after Amazon opened a checkout-free grocery shop in Seattle, accessible to the public.
As the UK's largest retailer, Tesco adopting such technology more widely would mark a major shift in how transactions in shops are conducted.
But retail analyst Steve Dresser told the BBC: "Recent stories about the level of theft at self-service checkouts - something that we've had for around 10 years in retail - leaves me to wonder about the obvious savings in checkout-free stores versus a hidden cost in terms of theft."
