A second case of meat from the offspring of a cloned cow entering the UK's food chain has emerged.
The Food Standards Agency said it came to light as it investigated an earlier case of meat from a Highlands farm bull grown from the embryo of a cloned cow being sold to consumers.
The FSA has admitted it does not know how many embryos from cloned animals have been imported into Britain.
FSA chief Tim Smith said he had no safety concerns about the meat.
However, he said any suppliers would require approval under European law.
The FSA had already traced two bulls born from embryos of a cow cloned in the US that were bought by a farm near Nairn, in the Highlands.
The first of the two animals was slaughtered in July 2009 and its meat entered the food chain.
The second was slaughtered on 27 July 2010, but its meat was stopped from entering the food chain.
But now it has revealed that meat from another offspring of a cloned cow entered the food chain.
The animal, called Parable, was born in May 2007 and slaughtered on May 5 2010.
The Department for Environment, Food and Rural Affairs (Defra) said: "The FSA is investigating how meat from the offspring of a cloned animal was allowed to get into the food chain. We will need to consider their findings, and Defra is liaising closely with them.
"If we need to change our procedures to ensure full traceability of cloned cattle and their offspring in the UK, then we will work with our European partners to ensure that this happens."
It also said it had carried out an "extensive campaign" with the FSA three years ago which "publicised widely the rules around cloned animals and progeny of cloned animals entering the food chain", adding that the information still appeared in the national and farming press.
American biotechnology companies are cloning animals that give high yields of milk and meat to use as breeding stock.
In 2008, the Food and Drug Administration in the US said meat and milk from cloned animals were safe for human consumption, and Professor Hugh Pennington, an expert on food safety from Aberdeen University, told the BBC he agreed with that assessment.
"People are concerned about playing God and that kind of thing... rather than producing products which are dangerous to eat," he said.
"There's absolutely no evidence for that, and I've got no expectation that any such evidence will ever emerge."
At present, foodstuffs, including milk, produced from cloned animals must pass a safety evaluation and gain authorisation under so-called novel foods regulations before they are marketed in Europe.
The FSA said it had not been asked to consider any such cases, but Mr Smith said that despite having a "first-class cattle tracing scheme" in place, the system was not perfect.
"It's a bit like the police being there and being an efficient service and us expecting no crime. It's inevitable that however good the system is, it ultimately relies on the honesty of the people who are participating in the chain.
"So it means that every farmer, every breeder, every processor has to come clean and tell us what it is they're actually doing. It's impossible for us to stand by each animal and watch what happens to it throughout its life cycle."
BBC rural affairs correspondent Jeremy Cooke said: "For years farmers have been battling to regain their reputation after the disasters of BSE and foot and mouth disease.
"What the industry can ill afford is yet another damaging controversy."
Meanwhile, Scottish Environment Secretary Richard Lochhead said consumers "deserve to know the origin of all foods they purchase" and he was "concerned to learn that the offspring of these animals have been reared in the UK for food production purposes without any authorisation from the Food Standards Agency".
Earlier this week, a British dairy farmer said he used milk from a cow produced from a cloned parent, but UK dairy industry body DairyCo said it was "confident" no milk from such animals had entered the human food chain.
Peter Stevenson, from campaign group Compassion in World Farming, said cloning was "at the sharp end of the inhumane selective breeding processes that are often involved in the intensive production of meat and dairy products".
"Many animals suffer in the pursuit of higher yields because they are being stretched to the limits of their physical capacity," he added.
David Bowles, from the RSPCA, which wants cloning banned, said: "The Food Standards Agency and the regulators and the government had no idea that any animal meat or animal milk had gone into the food chain.
"So it's really about showing there's transparency and that customers can trust what they go into shops to buy and at the moment that is in doubt."
In 2008, the European Food Safety Authority said "no clear evidence" had emerged to suggest any food safety differences between food products from clones or their offspring compared to products from conventionally bred animals.
"But we must acknowledge that the evidence base, while growing and showing consistent findings, is still small," it added.
Last month MEPs voted in favour of a law that would ban cloned meat and other animal products in the European food supply.
The legislation faces a next stage of consideration in September before it could become EU law.