Britain's food labelling war escalated last week when food manufacturers opposed to the introduction of a traffic light system to indicate a product's nutritional value launched a joint TV advertising campaign aimed at promoting an alternate consumer packaging guide.

A coalition of 24 companies has pledged a combined total of €6 million to an advertising war chest to be spent over the next 18 months on promoting its Guideline Daily Amount (GDA) system for food labelling.

The companies include Coca-Cola, Cadbury Schweppes, Kellogg's and Tesco. The ads will go head-to-head with a British Food Standards Agency (FSA) €1.5 million campaign promoting its own traffic-light system. Under this system food which is high in calories, salt, sugar and fat will be clearly stamped with a red light while more wholesome options are green-lighted.

The FSA believes its system clarifies the labelling system and helps consumers make more informed choices. The group of 24 completely disagrees and argues that the traffic lights could severely damage their brands and wreak havoc on the food industry at large.

People will not, the coalition argues, buy products which have red warning signs emblazoned on the front, even if the food is actually beneficial. To highlight the flaws in the green, amber, red system, they refer to cheese. Advocates of the GDA system point out that cheese is naturally high in fat and so will always have a red label despite the fact that it can still be eaten as part of a healthy diet so long as more than the GDA isn't consumed.

A second front in the war will also be opened this month when the British broadcasting regulator Ofcom implements a ban on advertising junk food on television before 9pm. Ofcom is to use the FSA's traffic-light system when deciding what can and can not be marketed directly to children.

This is particularly bad news for the breakfast cereal industry, worth over €1.8 billion in Ireland and Britain each year. An informal study carried out by Ofcom last year showed that by using the FSA system, the vast majority of advertising for breakfast cereals could not be broadcast before 9pm because the cereals are too high in fat, salt, and/or sugar and could be classified as junk food.

And last summer the consumer watchdog Which? analysed 275 breakfast cereals and found that 75 per cent had high levels of sugar, and almost 20 per cent had high levels of salt. Almost 90 per cent of cereals intended for the children's market were high in sugar, Which? found, ironic when you consider that the breakfast cereal industry has made much of its wholesomeness since Dr Kellogg invented the cornflake as a health food more than 100 years ago.

The companies backing the GDA campaign have already added the labels to over 10,000 products. Tesco is a major player in the move and has said the GDA labelling will be on all its products by the end of the year. The GDA is displayed on the front of the packaging in the form of an info-graphic and is considerably clearer than the almost entirely useless Recommended Daily Allowance (RDA) information it is to replace.

Tesco believes (or merely claims to believe, critics might say) that the GDA labels have already changed the buying behaviour of its shoppers. Speaking on BBC radio recently, a Tesco spokesman said it had information which indicated customers were using the GDA labels on the front of the packets of some 5,000 of its own-brand products to make changes towards healthier foods.

"We have seen it in ready meals, sandwiches and other product categories," the spokesman said. While he denied the implementation of the GDA scheme was done in an effort to safeguard sales, supporters of the traffic lights, including Sainsbury's, Marks and Spencer and Asda, say the GDA system is flawed and the traffic-light labels are easier to understand.

The FSA accepts that some consumers like the additional information the GDA provides but "without a traffic-light colour code our research showed that shoppers can't always interpret the information quickly and often find percentages difficult to understand and use." If traffic-light colours were added to products with GDA labels this would "reduce the confusion in the marketplace", it says.

Whatever happens with food labelling here and in Britain in the coming months, it is clear that changes are essential if consumers are to have a realistic chance of deciphering what is going into the food going into them.

While in Britain the government has adopted a proactive stance to food labelling as part of its ongoing war on obesity - particularly childhood obesity - our Government's position is less easy to establish.

The labelling system as it stands in Ireland is neither mandatory nor clear cut. Take the manner in which salt content often appears on food labels. Experts claim that a three gram reduction in our salt intake would save 900 lives in Ireland each year. While the Department of Health consistently stresses the need to lower salt intake from a 10g a day average to a recommended daily allowance (RDA) of 6g, it is not easy to establish how much salt is actually in our food.

Often the amount of sodium present per 100g rather than salt is listed. To calculate how much salt that equals, consumers have to multiply the sodium level by 2.5 and then multiply or divide that number by the number of grams they have consumed.

Hardly advanced maths, granted, but still an equation which is unlikely to be done by many time-pressed, mathematically challenged shoppers.