For millions it is the thorniest dilemma of the weekly shop. As the trolley glides to a halt in front of the egg display, the guilt-laden question is raised: organic, free range or battery?

For millions it is the thorniest dilemma of the weekly shop. As the trolley glides to a halt in front of the egg display, the guilt-laden question is raised: organic, free range or battery?

Ethically minded shoppers are increasingly plumping for the premium product - half a dozen organic eggs, laid by carefully cosseted flocks of feathered aristocrats with names like Columbian Blacktail. Despite being up to three times more expensive than those produced by battery hens, demand for organic eggs is rising at a rate of up to 20 per cent a year.

The industry, which until a decade ago was restricted to a few pioneering smallholders, is now worth £19m a year.

But even after paying a wallet-lightening £1.55 per half-dozen, the ethical consumer can at least depart the check-out safe in the knowledge that purely organic hens, who spend their lives in farmyards eating an entirely organic diet, will be responsible for tonight's omelette, soufflé or custard pie.

Think so? Think again.

What most consumers don't know is that current regulations mean very few of the 30 million eggs sold as organic in Britain every year are, in fact, purely organic. New rules will be introduced this year in an attempt to rectify this, but a coalition of producers, suppliers and a leading certifying body warned yesterday that the industry may collapse if forced to comply. The vast majority of egg-laying birds (pullets), destined to produce organic eggs, spend up to 18 weeks - nearly the first half of their productive lives - being fed non-organic food in the same indoor conditions as hens destined for other uses. It is only after a transfer process of six weeks, during which the pullets are moved to a laying farm with access to the outdoors and fed an organic diet, that the eggs can be classified as organic. Even then, the food given to the birds needs to be only 80 per cent organic.

Animal welfare groups argue that government regulations, which allow flocks of up to 12,000 birds with a density of nine birds per square metre to be described as organic as long as they have access to outdoor grazing, make a mockery of the hallowed "organic" designation.

The European Commission will require pullets to be fed a 100 per cent organic diet by this August. By January next year, producers will also have to feed their pullets an organic diet from birth and adhere to organic veterinary rules, which prohibit, for example, the use of antibiotic growth promoters.

But the rules, which have been accepted by Department for Environment, Food and Rural Affairs (Defra), are being hotly disputed by many in the sector who argue they will dramatically increase production costs and would push many organic egg farms out of business.

Currently there are almost no pullets being reared to organic standards from scratch and, it is claimed, 100 per cent organic feed will be too expensive. In addition, they say, such a diet might not be satisfactory for the birds. It is feared the result will be an increase in price of up to 15p per dozen, which will dissuade many from buying organic.

Richard Jacobs, the business manager for Organic Farmers and Growers, which certifies about 75 per cent of the 30 million organic eggs produced in Britain each year, said it would be a lot more expensive for producers to supply the birds that meet these new rules.

"We are concerned that a lot of them simply won't bother and will withdraw from supplying organic producers," Mr Jacobs said. "The result will be that we won't have any birds going into the organic system and the sector will collapse." Producers will meet Defra officials in the coming weeks to press for an extension to the deadline for imposing the new rules.

But there is another bugbear for organic producers: the differing standards required by the various bodies licensed to designate food as organic. In contrast to the large organic flock sizes permitted by Defra, the Soil Association requires its organic egg producers to limit their flocks to just 2,000 birds with access to open pasture. Critics of the current regulations argue they unfairly penalise farmers who adhere to stricter standards by allowing more intensive egg producers to qualify for the "organic" brand.

All of which makes life doubly hard for producers such as Giles Greenhough, who has spent £400,000 investing in organic techniques that meet Soil Association standards. His 6,800 birds, which produce up to 6,000 eggs a day for supply to Waitrose, are kept in flocks of just 1,800 and live in solar-powered mobile sheds in the Cornish countryside. Tending his Columbian Blacktails, Mr Greenhough said: "It is right that the consumer should know exactly what they're getting when they buy organic eggs and we operate to rigorous standards. We want to have organically reared birds eating organic food and we are striving towards it. But we can't do it overnight, particularly when we're dealing with so many ad hoc, garbled regulations."


* Under current rules, a chick being reared to produce organic eggs can spend the first 16 to 18 weeks of its life in an indoor rearing shed being fed a non-organic diet.

* The young laying hens, or pullets, are then transferred to the organic farm where they spend six weeks eating "organic" feed, after which their eggs are classified as organic.

* All organic hens can be given vaccinations and antibiotics in case of disease.

* An "organic" diet is defined by the Department of Environment, Food and Rural Affairs as including up to 20 per cent non-organic food. Producers say some ingredients cannot be obtained as organic or are prohibitively expensive.

* Despite plans to limit organic flock sizes to 3,000 birds, Defra has extended a limit of 12,000 birds until 2010.

* Producers estimate that organic rules will more than double the cost of a pullet and add £40 per ton of feed. This would add 15p to the cost of half-a-dozen organic eggs.