Tesco is weighing up whether to continue with its ad slogan “Britain’s Biggest Discounter” after being slammed by the Advertising Standards Authority (ASA).

The grocer – which last year waged war on discounters Aldi and Lidl with the launch of its discounter brands – said it is “considering all the feedback”.

The ASA this week upheld a complaint from Aldi, which argued that Tesco’s use of the claim “Britain’s Biggest Discounter” was misleading in reference to press and poster ads in July.

Aldi said Tesco could not claim to be a discount retailer because it does not have the same low-cost operation and limited product range of Aldi.

The ASA said Tesco’s claim was “ambiguous” and open to “a wide variety of interpretations”.

However, a Tesco spokesman said the ASA agreed the grocer could substantiate the claim in many ways, including “selling more cheap products than anybody else”.

He added: “The important thing for us is what our customers think and they have voted with their feet. Since we launched our discounter ranges more than 30 per cent of our customers are now buying the products and according to independent industry figures fewer customers are turning to Aldi.”

This week the ASA upheld a complaint made against Tesco by Asda over a TV ad in July, ruling its price comparisons were “misleading”.