Given its ease of access to grazing and water, Smithfield established itself as London's livestock market, remaining so for almost 1,000 years.
Royal Chef Selection is founded on the provision of quality meat, great service and extensive experience in the meat industry.
Police said the meatpackers had direct influence in the Agriculture Ministry so they could pick the inspectors who would visit their plants.
Those inspectors would produce sanitary certificates regardless of the adulteration of the products, police said.
Smithfield Market, a Grade II listed-covered market building, was designed by Victorian architect Sir Horace Jones in the second half of the 19th century, and is the dominant architectural feature of the area.
In the Middle Ages, it was a broad grassy area known as Smooth Field, located beyond London Wall stretching to the eastern bank of the River Fleet.