A water company's planners have been accused of "creating their own rules" when choosing a site for a massive sewage works in the South Downs.

Southern Water was told it would be destroying a tranquil haven if plans to build the £200 million waste water and sludge treatment works at Lower Hoddern Farm, Peacehaven, went ahead.

A five-week inquiry is hearing an appeal by the water company after East Sussex County Council failed to decide on the application for the plant.

It is the second inquiry, after plans to build it in nearby Portobello were turned down in 2000.

Matthew Horton, QC, for the council, said yesterday that in ignoring decrees to protect the South Downs, the company's planners were, in effect, "creating their own rules".

He said it was a priority to keep the Area Of Outstanding Natural Beauty safe as noted in the East Sussex County Landscape Assessment.

Campaigners, packed into a meeting room at the Meridian Centre, jeered as Karen Roberts, landscape witness for Southern Water, said the greenfield site was not part of the Downs but was instead "urban fringe farmland".

Mrs Roberts had already been heckled after she said the site was not tranquil.

Stan Cannon, whose home in Bramber Close, backs on to the site, produced a letter of complaint for the inquiry following Mrs Roberts comments on Tuesday.

He said: "I was dying of cancer 15 years ago and I was advised to come here for the peace and quiet. It worked, I'm still here.

"If the sewage plant is built that will all change. It will be absolutely horrendous."

Mr Horton argued there were scant reasons for placing the sewage plant on the greenfield site.

He cited Inspector Simon Gibbs's report into the Portobello site, which suggested there would be "formidable" objections to building it in Lower Hoddern Farm.

Mrs Roberts agreed the site was "an open landscape vulnerable to change".

Mr Horton replied that the plant was likely to wound the landscape.

He said: "You are proposing a sewage works on the South Downs, aren't you?"

The inquiry will help Secretary of State Ruth Kelly decide if she should approve the 12-hectare plant, which is the equivalent in size of 17 football pitches.