Campaigners have chalked up a major victory in their fight against plans to expand Witney's sewage treatment plant.

Campaigner Sheila Nicholson with the petition she presented to councillors

Oxfordshire County Council has told Thames Water, which runs the plant near the Ducklington roundabout, that a 'significant number' of householders could be affected by the smell if the site is upgraded to deal with more waste.

The council has told the company it must apply for planning permission to build a silo and install new machinery, and cannot do the work under existing planning rights as it had hoped.

New EU regulations mean sludge -- the matter left after sewage has been treated -- has to be treated again before it can be used on farmland as fertiliser.

Thames Water wants to expand sludge processing at its Witney plant from 9,000 to 17,000 tonnes a year.

Residents from areas like the Burwell estate opposed the idea, fearing it may cause a stink. Sheila Nicholson, of St Mary's Mead, collected more than 1,000 signatures on a petition against the development.

She said: "I think it's a major victory for all the people who signed the petition.

"I'm much encouraged, as it means Thames Water can't go ahead without further investigations. I think it's looking pretty bleak for them as their plans stand at the moment."

The council's environmental health department said the biggest concern was the smell created as sludge is loaded into lorries, a process which takes 15 minutes and would happen on average 10 times a day.

The report said: "I believe that odour could affect a significant number of householders in Witney as well as people working on the Thorney Leys Industrial Park."

Andrew Boyd, of Thames Water, said: "We're disappointed by the council's decision. We don't believe that the equipment we want to install would have a significant impact, and that includes odour. At the moment we're considering our options."

The company can appeal to Margaret Beckett, the Secretary of State for the Environment, or apply again with an environmental impact assessment.

David Harvey, from West Oxfordshire District Council, visited a Thames Water site at Farnham, in Hampshire, to see a similar treatment works.

He said: "On the last visit, rather than just being given the guided tour, the people on the trip went to the Sainsbury's supermarket across the road and asked them about the real impact the revised equipment had had.

"I understand they were horrified by what they heard."