The UK’s Advertising Standards Authority has told supermarket chain Asda not to use the claim “officially Britain’s lowest priced supermarket” in future advertisements.

Rival supermarket group Tesco had objected to three national press advertisements and a television commercial that claimed that Asda was Britain’s lowest priced supermarket. The adverts cited an independent industry survey by magazine The Grocer.

According to the ASA, Tesco said the claims were misleading, “because they were based on a limited and unrepresentative survey that analysed only 33 items and another survey had suggested that the complainants were cheaper”.

Tesco also said the word “officially” misleadingly implied the survey was carried out by a government department or industry body.

In its ruling, the ASA said that although Asda had won The Grocer 33’s annual award for the cheapest retailer in June 2004, with the cheapest average full-basket price in three of that year’s quarters, and that Asda had returned more cheapest weekly full baskets than any other retailer over the year and had won the annual award for the previous six years, the authority considered it too limited a price comparison to substantiate Asda’s claim to be “officially the lowest priced supermarket”.

In response to the complaint about use of the word “official”, Asda said The Grocer was considered by the retailing industry to be the “official” journal on all retail matters and that the magazine had announced the results of its survey with the headline, “It’s official: Asda is the UK’s cheapest supermarket for the seventh year running.”

However, the ASA ruled that use of the word “officially” implied the survey had been carried out by a government department, public authority, industry body or commercial body whose data commanded near-universal acceptance within the industry. The authority told Asda not to repeat the “misleading” claim.

Overall, the ASA concluded that the advertisements broke advertising standards codes and Asda was told not to repeat the claim.