The Advertising Standards Authority is investigating objections from the public to “misleading” posters, which show Dasani bottles sporting the word ‘pure’.
The complainants argue that, as the controversial product is filtered water fortified with vitamins and minerals, it cannot be described as ‘pure’.
If the ASA backs the complaints, Coca-Cola could be forced to change the brand’s advertising - a hefty part of its £7 million marketing spend.
It could also face a packaging overhaul if trading standards officials, ordered by the Food Standards Agency to investigate, find the claim breaks labelling guidelines. Coca-Cola Enterprises has so far been defiant in the face of media coverage calling the product “expensive tap water”.
A spokesman said the company was cooperating fully with the FSA and Dasani’s labelling complied with all relevant laws and regulations.
Meanwhile, retailers said it was too early to tell if the media barrage would affect the brand’s sales in the long term.