Consumer group Which? has lodged a complaint with the Advertising Standards Authority, suggesting that Kellogg's marketing of CoCo Pops Straws is "misleading and socially irresponsible".

The consumer group has taken issue with a Kellogg television advert promoting chocolate-coated biscuit straws as a way to increase milk consumption. The advert, which features a mother giving her son a pet cow to get him to drink milk, carries the strapline: "How far would you go to get milk into your kids? Well here's an easier way. New Coco Pops Straws is a totally different kind of breakfast, delicious cereal straws with a yummy chocolatey lining, your kids won't be able to stop slurping. New Coco Pops Straws make milk more fun."

Sue Davies, Which? chief policy adviser, said: "This advert sends a confusing message about what is healthy and what is not to both children and parents. It is yet another example of the irresponsible and underhand marketing techniques used to push unhealthy food to children.

"The close association between chocolate and milk and the implied message that the chocolate straw is wholesome if it is consumed in this way is visually and verbally unclear."

Which? argue that Kellogg's is deliberately marketing an unhealthy product based on its health benefits. Davies emphasised the high sugar content of CoCo Pops Straws.  "The amount of sugar that a child would be consuming every morning if they ate this product as a breakfast cereal is equivalent to a 'two finger Kit Kat' chocolate bar which contains 10.4g of sugar per bar.

"Kellogg's claim that a 31g serving provides at least 17% of the recommended daily allowance of vitamins and minerals. However there is no justification for encouraging children, through advertising to consume a high sugar product at breakfast when the same vitamin content can be provided by other, healthier means."

In response, Kellogg said in a statement: "A serving of Kellogg's Coco Pops Straws provides 11% of the GDA for sugar, which is half the amount of sugar that would be contained in two slices of toast with jam or marmalade."

"The TV advert referred to is speaking to mums through a 'Making Milk Fun' campaign that also focuses on communicating to them that there is more than one way of encouraging kids to consume milk as part of a balanced diet."

The Which? complaint comes just one month after the US consumer group the Centre for Science in the Public Interest launched a lawsuit against Nickelodeon and Kellogg for marketing unhealthy foods to young children.

Michael Mackman, Kellogg spokeswoman, told just-food that the company did not identify a link between the two cases. "Kellogg's will continue to liaise with trade and consumer organisations and assist them with any investigations as required," she said.