Food manufacturers and retailers have always prospered by giving customers what they want - and signpost labelling provides an ­opportunity to do just that. Shop­pers want healthier food and they want to be able to find it ­quickly and easily - clear front-of-pack labelling is key to helping them achieve this. The progress made by industry so far is encouraging. The one issue that remains is the way in which this infor­mation should be presented.

As an evidence-based organisa­tion, our recommendations must be based on robust research, which is why we conducted the most exten­sive piece of published research to date. We asked more than 2,600 ­people to trial four schemes to identify which they preferred and test which helped them make healthier choices. The results were clear: red, amber and green colour coding is critical in helping shoppers use and understand front-of-pack labelling. Shoppers also said they wanted to see signposts on foods that are hard to judge ­nutritionally, such as ready meals , burgers and cereals.

On the basis of this evidence, the FSA Board recommended four core principles for industry to help consumers make informed ­choices. These prin­ciples enable companies to develop individual schemes that enhance their own distinctive branding while ensuring clarity and consistency across brands.

Companies can add GDA information but their inclusion is not a core principle, as our research found that many shoppers had trouble inter­preting percen­tages and could not use GDAs ­correctly. Inclu­ding traffic light colours seems to be the sticking point. ­Tesco and five manufacturers - Danone, Kellogg, Kraft, Nestlé and PepsiCo - have all forged ahead with signposts using neutral ­rather than indicative colours. Inevitably we are disappoin­ted they have chosen to ignore what in our research consumers said they so clearly wanted - but in the end it will be consumers who hold companies to account and show us what works most effectively.

The traffic light analogy should not be taken too literally. A red dot on the front of a pack does not mean 'stop, don't buy me'. In our research, people said a red rating would make them think about how often to eat that food. In practice, Sainsbury has told us that shoppers have been influenced towards healthier items by its Wheel of Health but have not boycotted foods with a higher number of red wedges. Justin King tells us that this is actually driving product development.

Detractors have parodied signposting as a prescription for nanny­ing and nonsensical judgements. But this isn't about ­labelling foods 'good' or 'bad', nor is it about put­ting red spots on choco­late bars or soft drinks that we already know we should eat less of. It's about helping busy people to quickly assess the content of more complex foods such as ready meals or pizzas.

The core principles are prag­matic and progressive: they facili­tate choice and promote competi­tion and crea­ti­vity. Sainsbury and ­Waitrose's schemes meet these princi­ples, as does Asda's proto­type. We welcome The Co-operative Group's plans to adopt a scheme that also meets our criteria. It's encouraging to have consistency across more than a third of the food retail market, with others waiting in the wings.

Poor diet contributes to serious illnesses and better information is part of the solution. The FSA's next move, together with stakeholders, is to set up research to evaluate exis­ting and planned schemes, so that we can all learn from what works. The industry's co-operation and support are critical.