"This is an unacceptable situation and people have a right to expect that the food they are eating is correctly described," the agency said.
The furor over the Findus lasagna prompted humor as well as outrage on Twitter.
"If you think the Findus Lasagnes are bad, you should try their Filly Cheese Steak," wrote James Martin, posting as @Pundamentalism.
Comedian Adam Hills, posting as @adamhillscomedy, joked: "Those horses wanted to be uncovered in British Lasagne. Even the brand was called Findus."