The china clay industry in Cornwall was started nearly 300 years ago by English China Clays, which was taken over by Imerys in 1999.

BBC: Imerys china clay in Cornwall announces job losses

The French company, Imerys, which operates in Cornwall and Devon, said the cuts were a result of the "difficult market situation" and increased costs.

BBC: Imerys china clay in Cornwall announces job losses

Ms Lister said, as a significant landowner in mid Cornwall, fly-tipping near Imerys's entrances and access points had become "common hotspots" for dumping waste.

BBC: Imerys land

Imerys Minerals acquired Goonvean Aggregates in November, taking 140 Goonvean staff.

BBC: China clay pit

Yvonne Lister, of clay company Imerys, said there had been a steady rise in illegal fly-tipping on its land, over the last two to three years.

BBC: Imerys land

As both Imerys and Goonvean had been active in the extraction, processing and supply of kaolin products from deposits and facilities in Cornwall before the merger, the OFT concluded there was a realistic prospect the merger could result in a "substantial lessening of competition".

BBC: China clay pit