A man accused of dumping hazardous waste into a quarry may have caused £9billion in damage to North Somerset’s drinking water supply.

Mark Foley, of Mill Lane in Cardiff, held a permit in the name of his firm M E Foley Contractors LTD to dump non-hazardous waste in Stowey Quarry, close to Chew Valley Lake - which is one of Weston's sources of drinking water.

But Foley, and the firm, are accused of violating the terms of the permit, and instead dumping harmful substances, including residues created in the process of destroying cars.

The Environment Agency believes the contaminants may have 'leached' through soil from the quarry to the lake.

Brendan Moorehouse, prosecuting for the Environment Agency at North Somerset Courthouse on Monday, said: "With the huge harm, the huge cost of clean up and the risk to public health, this is an extremely serious case.

"The minimum cost of clean up is in excess of £50million, and should the contaminants leach into the Bristol city water supply it could cost up to £9billion."

Foley, aged 62, will appear at Bristol Crown Court on November 11, charged with contravening an environmental permit and disposing of controlled waste in a manner likely to cause pollution or harm to human health.

He pleaded not guilty.