More cases of contaminated meat may be revealed within days, the Government has warned as it raised fears that an international criminal conspiracy was behind the horse meat scandal.
Environment Secretary Owen Paterson said the next set of results on all retailers' and manufacturers' processed beef products could reveal further traces of horse meat. "There may well be more bad results coming through, that's the point of doing this random analysis," Mr Paterson said.
The results, ordered by the Food Standards Agency (FSA), are due on Friday, Mr Paterson said retailers have agreed plans to improve their food testing, adding that they hold the "ultimate responsibility" for making sure their products do not contain horse meat.
One of the food companies at the centre of the horse meat scandal has said it is considering taking legal action against its suppliers.
Frozen foods firm Findus, which has taken its beef lasagnes off shelves after some were found to have up to 100% horse meat in them, said it was looking into legal action as an internal investigation "strongly suggests" that the contamination "was not accidental".
Mr Paterson spoke after attending an emergency meeting with bosses from leading supermarkets, trade bodies and the FSA to discuss the scandal, which has seen chains including Tesco, Lidl, Aldi and Iceland withdraw some products.
He said supermarkets and trade bodies have already begun plans to carry out more testing and report their results on a quarterly basis. They agreed that consumers should be compensated if they have bought withdrawn products with no questions asked, he said.
Mr Paterson added: "It's a question of either gross incompetence, but as I've said publicly and I'll repeat again, I'm more concerned there's actually an international criminal conspiracy here, and we've really got to get to the bottom of it.
"If there's a criminal act we will work with the authorities wherever they are to ensure the appropriate measures are taken. This is a conspiracy against the public. Selling a product as beef, and including a lot of horse in it is fraud."
Scotland Yard officers have met representatives from the FSA, although there is currently no official police investigation.