Tesco is threatening to complain to the Advertising Standards Authority about Ocado's latest advertising campaign.

An advert run this week by the online retailer claimed it would match Tesco on 3,500 branded products, but Tesco claims it is still cheaper on 2,500 products, according to the Daily Telegraph.

“We are delighted that Ocado sees Tesco.com as the benchmark for low prices but if they promise their customers that they are going to match us on price, they owe it to them to at least try,” a Tesco spokesman said. “These independent figures appear to show that their claims are nothing more than a gimmick.”

Ocado CEO Tim Steiner said: “We are confident that we have matched over 4,000 items this week. If they send us a list of products we haven't yet matched, we will match them.”