Two ads were banned by the ASA because the comparison used Tesco products on special offer and others that would not be considered part of an average weekly shop.
One ad showed a shopping trolley of goods, with the words: “Asda£76.15. Tesco£49.59. Why pay more at Asda? Includes Tesco products on promotion.” A similar ad was aimed at Morrisons.
An ASA spokeswoman said: “It is not the case that the products used were cheaper because there were specific price reductions.”