Thirteen people have been convicted in connection with Europe’s biggest ever illegal veterinary medicine business in which more than £6million of products were smuggled to the UK, risking the health of people and animals, says a press release from the Veterinary Medicines Directorate (VMD) of the U.K.

The ringleaders, Ronald Meddes, 73, and his wife Regine Lansley, 62, sold unauthorized and prescription-only medicines to more than 4,000 British customers from their properties in France and from warehouses in Belgium and Kent.

Six other key players unlawfully distributed the products on the black market to British farms, stables, kennels and vet surgeries. Three other major customers were convicted, as well as one man responsible for laundering the proceeds.

Steve Dean, Chief Executive of the Government’s VMD, which prosecuted the case, said: “This was a significant commercial enterprise which seriously attacked the principle of safe and effective veterinary medicines. Incorrect use of medication of unknown origin and dubious quality compromises animal health and welfare, increases the risk of harmful residues in the food chain and raises the spectre of unnecessary antibiotic resistance.”

The medicines included non steroidal anti-inflammatory drugs, anabolic steroids, antibiotics, sedatives, and pain control treatments for a variety of species including horses, cows, sheep, pigs and household pets.

To be imported and sold for use in the UK all veterinary medicines must be authorized to ensure they are safe and effective, and many must be prescribed by a veterinary surgeon. Even where medicines are authorized they must be distributed and sold through licensed outlets where trained staff are available to provide the necessary advice on safe use.

Read the full press release here.