Meat from the offspring of a cloned cow has entered the food chain in Britain, food safety officials report.
The Food Standards Agency (FSA) made the discovery as it probed a report that milk from the offspring of a cloned cow had been put on sale for public consumption.
As part of this investigation, officials identified two bulls born in Britain from embryos harvested from a cloned cow in the United States, both of which had been slaughtered.
Meat from one had entered the food chain and "will have been eaten" and meat from the other had been prevented from entering the food chain, said the FSA.
The disclosure will heighten concerns among farming campaigners in Britain, where the subject of producing foodstuffs from clones and their offspring is highly controversial.
"The first (bull), Dundee Paratrooper, was born in December 2006 and was slaughtered in July 2009. Meat from this animal entered the food chain and will have been eaten," said an agency spokeswoman.
"The second, Dundee Perfect, was born in March 2007 and was slaughtered on July 27 2010. Meat from this animal has been stopped from entering the food chain."
The probe was launched after a report last week in the International Herald Tribune newspaper.
The paper quoted a British dairy farmer, speaking anonymously, saying that he was using milk from a cow bred from a clone as part of his daily production.
The FSA said it had traced a single animal, Dundee Paradise, believed to be part of a dairy herd, but could not confirm that milk from the animal had entered the food chain.
Under European law, foodstuffs, including milk, produced from cloned animals must pass a safety evaluation and gain authorisation before they are marketed.
The FSA, which is responsible for the assessment of "novel foods" produced by cloned animals and their offspring, said it had neither granted any authorisations nor been asked to do so.
Campaigners have voiced concerns about the possibility of produce from cloned farm animals entering the food chain.
Emma Hockridge of the Soil Association, which campaigns for organic farming, said there were concerns related to the safety of products from cloned animals and that they could reduce genetic diversity.
But Dairy UK, which represents the industry in Britain, has insisted the products present no danger.
"Milk and meat from the offspring of clones does not present any food safety risk," it said in a statement.