Families claim they are being trapped in their homes by a smell "similar to a rotting animal" that they believe is human waste.

Residents of Crelly, near Helston, say that large mounds of biosolids (human waste sludge) have been piled in a field beside the B3297, which a public footpath goes directly through, and tractors had now started spreading the muck on the field, just a few metres from their cottages.

One woman, who asked not to be named, said: "Our hamlet of Crelly near Helston is being subjected to the most horrific smells of what can only be described as similar to a rotting animal.

"The smell radiating from these mounds can be smelt several miles away as it travels on the wind.

"Stepping out the front door makes stomachs turn. The smell has trapped us in our homes."

She said what made matters worse was that tractors loaded with muck had been travelling from one part of the farm and down the public highway to to other areas.

The muck had been dropping off the spreader and the wheels of the tractor, and finding its way on to residents' boots, dogs, bicycles and pushchair wheels.

She added: "Most residents have dogs and children, and are concerned about what bacteria might be entering our homes after coming in to contact with the waste.

"Families are really angry that we have to endure this smell."

There are also fears that, with the farm covering two sides of a valley and a water course down the middle, the recent heavy rain may has caused the waste to run into the river.

Residents have appealed to the Environment Agency (EA) for help and asked officers to investigate.

A spokesperson for the EA told the Packet: "The Environment Agency is fully aware of the activity underway near Helston and the operator involved.

"Septic tank waste is being stored on the site and being spread to land legitimately under the Sludge Use In Agriculture Regulations.

"We recognise local people are very unhappy, but as long as the waste does not actually cause pollution and is managed in a way to prevent pollution by incorporation into agricultural land, and that sewage related debris is screened and not spread to land, then the activity is not illegal and does not require a permit."

Septic tank sludge is the settled solids from the bottom of a domestic septic tank. These are passed through a screen to remove ‘sewage related debris’ – the element that does not biodegrade. This debris is stored separately and then either taken to landfill or an incinerator for disposal.

The spokesperson added: "Where the activity causes offensive odours, local residents can complain to the Public Protection team at Cornwall Council to resolve the issue."

The farmer involved told the Packet it was a one off situation, although warned that there were still five or six loads left to spread before finished.

He said: "I'm not planning on doing it on a regular basis. The land is going on organic conversion on January 1 and it's a way of me increasing the organic matter in the field beforehand.

"It's not very nice stuff to deal with, but it's an organic fertiliser going on."

He explained that it was composted sewage, supplied by a subsidiary of South West Water, adding: "When people flush the toilet they seem to think it's going to disappear - it isn't.

"From an organic perspective, it's an absolute travesty that these nutrients are [often] being pumped into the sea rather than going into the land.

"It's a lot more environmentally friendly to recycle that than digging up phosphate from North Africa."