An EU ban on battery cages comes in to effect on 1 January 2012, from when egg producers are required to provide hens with larger and more comfortable cages, which include nesting and scratching areas that allow more natural behaviour.

The UK has long been calling for a tough EU enforcement regime to ensure welfare standards are driven up and prevent producers who have not dispensed with battery cages from profiting.

To overcome the fact that no European agreement was reached on enforcement, the British government has instead been working closely with the domestic egg industry, processors, food manufacturers, the food service sector and retailers to reach a voluntary consensus that they won’t sell or use battery-farmed eggs which will help British consumers to avoid unwittingly buying them.

Agriculture Minister Jim Paice explained: “It is unacceptable that after the ban on battery cages comes into effect, around 50 million hens across Europe will still remain in poor conditions."

“We have all had plenty of time to make these changes, but 13 EU nations have not done so. The UK egg industry alone has spent £400million ensuring hens live in better conditions. It would be unthinkable if countries continuing to house hens in poor conditions were to profit from flouting the law.

“British shoppers should be reassured that as long as they buy food containing eggs from those companies who have guaranteed not to use or sell eggs from battery cages, they will be supporting higher welfare standards and British egg producers.”

The Animal Health and Veterinary Laboratories Agency (AHVLA) will use ultra violet light to identify batches of eggs that were not laid in the new, more welfare friendly cages. UV light picks up small marks left in the shell immediately after it has been laid, before it hardens. Any eggs which only show a pattern of wire marks will have been laid in the old battery cages, and will not be allowed to be sold as class A (whole) eggs.

With many retailers and major food suppliers putting in place stringent traceability tests to guarantee they will not supply eggs produced from illegal conventional cages or use them as ingredients in their own brand products, it will be difficult for producers who have not complied with the EU directive to find an outlet in the UK.

Jim Paice added: “We’re taking action to protect UK consumers and the egg industry by hitting producers who flout the law where it hurts – in their pockets."

“I want to congratulate the many major supermarkets and food businesses who have joined with us to stand up for animal welfare by saying they won’t sell or use eggs produced in battery cages, making it far less likely that the British public will be buying them.”

The RSPCA is pleased that Defra has announced some measures to try and protect shoppers from illegal shell eggs but it appears nothing will be done to reliably check whether or not imported liquid eggs come from hens kept in illegal barren battery cages.

The RSPCA's calls for an intra-community trade ban appear to have fallen on deaf ears – despite research showing that 78 per cent of the public in England and Wales wanted to be protected from illegal eggs which will not meet minimum welfare requirements.

With less than a month to go before the ban the European Commission’s efforts have been at best shambolic.

The RSPCA wants UK importers, caterers, processors, food manufacturers and retailers to protect the public, they are morally responsible for ensuring the products they sell do not contain illegal eggs.

The RSPCA also urges the European Commission and member states where there is illegal production to ensure they rigorously enforce the new legislation to improve the lives of millions of hens still being kept in cruel barren battery cages.

NFU poultry board chairman Charles Bourns said: “We welcome the enforcement measures being taken by the Government but our members will certainly be bitterly disappointed that it has not been possible to take tougher action."

“We are concerned that although the Government has repeatedly pledged its support for the industry, it cannot prohibit the use of illegal egg products and food manufactured from such products. Although we are pleased to see the support of some UK retailers and food manufacturers on this, there are still a number of companies who have yet to make this commitment."

"Further to this, we would like to see retailers and food manufacturers showing their support for the whole of the British egg industry by offering a fair price for all legal eggs and egg products to recognise the investment that has been made in all production systems in readiness for 1 January."

“The UK egg industry should not be disadvantaged for embracing new higher welfare systems and the Government’s announcement is not what UK egg producers needed after they have invested so heavily and met the requirements of the law.”

Compassion in World Farming is also warning customers that they could unwittingly be eating illegal eggs in the New Year.

But there is an easy solution for consumers. Compassion’s director of Public Affairs, Joyce D’Silva, said: “This means consumers will have to be extra vigilant. We’d say the best way to be sure you’re not eating illegal and cruelly-produced eggs is to check that the label on your pasta, cake or ready meal says that any eggs are free range or organic.”

She added: “It’s terrible that we are in this position in the first place – the ban was voted for in 1999. There should be red faces in some European countries. Given the years they’ve had to prepare for this ban, there are no excuses. We are calling on the European Commission to prosecute those countries who have failed to comply.”

Ms D'Silva said: “The EU should be rightfully proud of the ban on barren cages. It’s a great achievement for animal welfare. It’s essential now to make sure that the ban is properly enforced, so consumers can buy products with confidence that they don’t contain illegal eggs.”