Asda, the UK unit of Wal-Mart, has played down reports that it is trying to emulate Sainsbury's following the use of a slogan first coined by its rival in the 1950s.

In a series of national print adverts this weekend, Asda declared: "good food costs less at Asda".

The use of the slogan, with its striking similarity to the catchphrase "good food costs less at Sainsbury's", has prompted speculation that Asda is attempting to boost its appeal to middle-class shoppers - the bedrock of Sainsbury's traditional customer base.

However, a spokesperson for Asda told just-food that it was a "misconception" that Asda does not already appeal to middle-class consumers.

"Our customer base has changed a lot in the last five years, and particularly in recent times when people have been re-evaluating their spending and the meaning of value," the spokesperson said. "We have just as many BMWs and Audis in the car park as we have customers getting off the bus."

According to the spokesperson, Asda has boosted its appeal to middle-class consumers by improving the quality of its own-label ranges.

As to claims that the supermarket group is emulating Sainsbury's, the spokesperson insisted: "Nobody has a monopoly on the English language."