The FSA may have reached a compromise solution this week in the battle over front-of-pack nutrition labelling, but doubts remain over the legality of traffic lights under the European Commission's forthcoming health claims regulation.

Despite opposition from Asda, Which? and health charities, the FSA board voted in favour of a single voluntary approach, which combines GDAs with either traffic-light colours or text, such as high, medium, or low, but preferably both.

However, as the FSA's head of nutrition Clair Baynton admitted during its board meeting in Cardiff this week, there is still some confusion as to which European regulations traffic lights fall under. If the commission considers traffic lights to be just information, they will fall under the Food Information Regulation and there will be no issue. But if it suggests a traffic light, along with the word "low" as a description, is a health claim, they will be covered by the Health and Nutrition Claim Regulations and will not be permissible on pack until they have been formally approved.

Baynton said the FSA did not believe there would be a problem, but had asked the commission for clarification and was currently awaiting a response.

One industry source said the health claim regulations, which are currently being assessed by the European Food Safety Authority, raised serious questions over the future of traffic lights. "If the commission says these are health claims, they need to be approved and until then they can't be used."

The FSA's proposals were generally well received by the industry as it involved a compromise between the two competing schemes and appears to allow companies time to develop a solution that works for all.

"This leaves us in a better place to have constructive dialogue on labelling," said FDF director of communications Julian Hunt. He pointed out, however, that there were two further "known unknowns" that could have a major impact on the issue the forthcoming general election and the European labelling proposals, which are due to be voted on in the European Parliament for the first time next week.

"It remains to be seen if food companies will invest further in changing their approaches at the current time given uncertainties about the detail of the nutrient profiling approach, future EU regulation and the potential impact of a change in government," added British Nutrition Foundation director general Judith Buttriss. "But credit to the FSA that it has revised its approach to take account of findings of research it funded."

Asda was the most upset of the big supermarkets by the decision. Prior to the vote it jointly signed a ­letter to the FSA claiming that allowing companies to use just two of GDAs, traffic lights and text would "create more rather than less confusion among consumers".