Food industry-backed front-of-pack nutritional signposting is 'fundamentally flawed', according to the National Heart Forum (NHF).
The pressure group claims that the scheme, which is being promoted in competition with the Food Standards Agency 'traffic light' labels, "can mislead and confuse consumers trying to choose healthier foods when they are shopping".
Today's publication of the charity's findings is likely to up the stakes in the on-going battle for the hearts and minds of consumers between the UK food watchdog and industry heavyweights over nutrition labelling.
The heart charity looked at front-of-pack labels which display percentages of Guideline Daily Amounts (GDAs) currently appearing on products from a number of manufacturers and on many Tesco own-brand goods.
It claimed that these labels are misleading and confusing as companies often mix GDAs with other claims and promotional labels on the front of food packaging.
"This report shows that some manufacturers and retailers are failing their customers by using nutritional food labels which are overly complex and misleading," said Jane Landon, deputy chief executive of the National Heart Forum.
"Some even appear to be manipulating the front-of-pack label to promote their products rather than to inform their customers."
Guideline Daily Amounts represent population goals for particular nutrients. The NHF said that rresenting these as percentages on the front of food packaging suggests to the consumer that these are daily targets.
"Without reading the small print on the back of the packet it is not clear that for fat, saturated fat, sugar and salt these figures represent limits rather than targets," said Landon.
"With as little as four seconds for each purchase, what consumer's need to be able to see 'at a glance' on the front of the pack is whether a product is high, medium or low in key nutrients."
This of course is the goal of traffic light labelling. Last month, the FSA launched a promotional campaign for consumers with TV advertisements, poster campaigns, and ads in the national press.
"Our new labelling TV ads, like the traffic light approach, are clear and simple with the beauty being that these labels speak for themselves," said FSA chair Deirdre Hutton in a release.
"Our extensive and published research demonstrates that the use of traffic light colours is key to helping people interpret nutritional information on foods. We want to highlight to shoppers that these labels are now out there and really can help us all to make healthier choices."
The FSA's traffic light system rates each product as high (red light), medium (amber light) or low (green light) in the four key nutrients (fat, saturated fat, salt and sugar), is used by firms including Sainsbury's, Waitrose, the Co-Op, Marks and Spencer and Asda.
However, some of the UK's biggest food manufacturers including Danone, Kellogg's, Kraft, Nestle and PepsiCo and retailers Tesco and Morrisons argue that, while the GDA scheme is criticised for being too complicated, the FSA's traffic light labelling scheme is far too simplistic.
And in response to the FSA's publicity scheme, these companies have launched a new campaign called 'know what's going inside you.' The TV, online and print campaign - which will run between January and August - aims to explain how people can use Guideline Daily Amount (GDA) labels to assess the calories, sugars, fat, saturates and salt that are suggested for a balanced diet.