The Food Standards Agency is also looking into claims that the firm also mixed rotten pork with fresh meat.

It is understood the meat may have ended up in many UK supermarkets.

Farmers Weekly, which first reported the story said that the company was passing off industrial scale quantities of foreign pork as British.

It said this may have been in products up until at least 2020 and could have been included in many items such as ready meals, quiches and sandwiches sold in a number of UK supermarkets, with schools, hospitals, care homes and prisons also indirectly supplied.

The Food Standards Agency is not naming the business involved whilst it continues to gather evidence and so as not to prejudice any possible future action by the courts.

Based on the investigation so far, the FSA said "There is no indication that food is unsafe or there is an increased risk" to consumers.

"Criminal investigations take time and need to be done with due process and fairness. The FSA will work tirelessly on behalf of consumers to ensure that this criminal investigation is done to the highest possible standards," Emily Miles, the chief executive of the Food Standards Agency added.

Retail industry lobby group, the British Retail Consortium said it could not comment on an ongoing investigation.

"Whilst we cannot comment on an ongoing investigation, retailers will support the FSA with its investigation into the individual supplier in question," it added.

It is understood that the Food Standards Agency's National Food Crime Unit (NFCU) started its initial investigation into the firm in September 2021.