The Australian Competition and Consumer Commission (ACCC) is suing Coles in a lawsuit described as “the case of the century” by a former ACCC boss.

Yesterday, the ACCC accused Coles of a “planned” campaign to mislead customers with fake or “illusory” discounts on hundreds of common household items from dog food to yoghurt and bottles of Coke.

The consumer watchdog claims the supermarket giant jacked up prices for a short time before cutting them and including items in the “Down Down” promotion.

It claims the “Down Down” price was actually more than, or the same as, the regular price.

In evidence this morning the judge overseeing the case, Justice Michael O’Bryan, asked Coles to explain what it was telling customers with its prominent marketing campaign, featuring giant red hands pointing down.

“It’s really asking a bigger question about what ordinary consumers understand about the Down Down program,” Justice O’Bryan said.

“I don’t know if I’ve seen a statement from Coles which directly answers that question.”

In response, legal counsel for Coles John Sheahan KC said: “In terms of what consumers would take from the advertising campaigns and the red hand — not much.”

“It’s an indication that Coles is trying to keep prices low,” he said.

Justice O’Bryan probed further, asking if Coles would accept that “Down Down” was a promotion and showed a discount.

“Yes,” Mr Sheahan responded.