British authorities were, according to The Guardian, aware that tonnes of condemned horsemeat was being imported for use by suspected fraudsters as long ago as 1998 but failed to investigate the criminal networks involved fully for lack of resources.

Over 15 years ago, environmental health officers from Rotherham council investigating a conspiracy in which hundreds of tonnes of unfit poultry meat was recycled in to the human food chain, discovered that regular shipments of around 20 tonnes each of frozen “ponymeat” from China had been arriving at UK ports for months.

The horsemeat consignments had been condemned for the human food chain by the Chinese authorities but could have been used legally to make petfood, according to a source involved with enforcement. However a paper trail showed the horsemeat going in to cold stores licenced for the human food chain rather than for petfood and then disappearing in a separate suspected fraud, the source said.

A spokesperson for Rotherham council confirmed that at the time it had investigated “significant concerns relating to a wide range of food stuffs, including poultry, ‘ponymeat’, red meats, fish and frozen vegetables”. Convictions were secured over the poultry, but no one was charged in the other suspected cases.

The chain of brokers and cold stores through which the horsemeat was passing overlapped with a criminal chain in which condemned poultry meat that was green with slime and covered with faeces was being cleaned up with chemicals, repacked and relabelled with faked official health marks and then moved in to the human food chain, the source said. The fraudulently mislabelled chicken and turkey was sold across the UK to food manufacturers, schools and retailers including the discount supermarkets Netto and Kwik Save.

FSA and police investigations into the 2013 horsemeat scandal have uncovered a similar pattern, in which imported horsemeat passing through a system of brokers and cold stores appears to have been repacked and relabelled with faked official health marks as beef, the Guardian has been told, although they have not proved where exactly the fraud of mislabelling took place.