A public inquiry into whether to build a giant sewage works will start today.

A planning inspector will begin hearing evidence for and against building a £200 million plant at Lower Hoddern Farm, Peacehaven.

The plans include a seven-mile tunnel from Black Rock, Brighton, pumping stations at Marine Drive, Roedean, and Portobello, Telscombe Cliffs, and a 1.5-mile sea outfall at Friars' Bay.

Campaigners have called for hundreds of people to attend the first hearing which starts at 10am at the Meridian Centre, Peacehaven.

Southern Water originally applied to East Sussex County Council and Brighton and Hove City Council for permission to build the works, which have been labelled "Poohaven" by protesters.

When the councils failed to make a decision within the time limit, the firm appealed to the Planning Inspectorate.

The inquiry is expected to last about five weeks.

Southern Water will be represented by two QCs.

Des Turner, MP for Brighton Kemptown, is planning to attend today.

He said: "I hope the inspector will agree with me that this particular site is completely inappropriate and flies in the face of Government planning policy, which is that you don't build on greenfield sites.

"It is going to be ugly, intrusive, noisy and smelly. It is very unfair to impose this on Peacehaven.

"The alternative sites on Southern Water's original shortlist could still be developed."

East Sussex County Council is expected to ask for an adjournment today.

John Hodgson, chairman of the Peacehaven Residents Opposed to Urban Development group, said: "We shall be strongly opposing this."

The works, which would serve 250,000 residents in Brighton and Hove, Woodingdean, Ovingdean, Rottingdean, Saltdean, Telscombe Cliffs and Peacehaven, would enable the area to meet EU standards on waste disposal.

Each day 95 million litres of water are pumped out to sea having had only preliminary treatment.

It is one of only a handful of UK locations failing to meet standards. Enforcement action has begun with the European Commission referring the Government to the European Court of Justice for failure to comply.

Richard Price, Southern Water's project director, said: "We must press ahead to secure a clear decision on this vital scheme.

"However, we have been keen to ensure the council continues to consider our scheme within the local planning process, which is why we have continued to work closely with officers to resolve their few outstanding matters of concern."

The firm originally wanted to extend its existing Portobello treatment plants at Telscombe Cliffs but its application was turned down in March 2001 following a public inquiry.

The new inquiry is due to end on Friday, July 28.

The inspector will report his findings to Ruth Kelly, Secretary of State for Communities and Local Government, who will make the final decision.

East Sussex County Council's planning and highways sub-committee is also due to consider a report today about a duplicate application for the works, currently going through its planning system.