The Slough Trading Estate founded in Slough, Berkshire in 1920, was an early business park in the United Kingdom. According to the estate's owners and operators, SEGRO (formerly Slough Estates plc), Slough Trading Estate consists of 486 acres (1.97 km²) of commercial property in Slough and provides 7,500,000 sq ft (700,000 m²) of accommodation to 500 businesses and has a working population of about 20,000 people. Slough Trading Estate is the largest industrial estate in single private ownership in Europe. There are over 600 buildings. The Estate is home to 400 tenants from countries including America, Italy, Japan, Germany and Korea. Companies using the park include, Fiat Group Automobiles UK Ltd, Centrica, Yell, Electrolux, GlaxoSmithKline, Mars Confectionery, ICI Paints, Virgin Media, O2, the datacentre operator Network-i and OKI Printing Solutions.