More than 80 people took to the streets today to demand plans for a sewage treatment plant are ditched for good.

Fears a huge upgrading of the Portobello treatment works at Telscombe Cliffs was once again being considered by Southern Water sparked a repeat of the protests of three years ago.

Des Turner MP for Brighton Kemp Town, joined with members of the Campaign for Residents Against Portobello and concerned residents, some of them carrying placards saying Save Our Cliffs and No Portobello.

Despite assurances by Southern Water that no new plans have been submitted, they gathered outside the gates of the existing treatment works close to the beach at Telscombe Cliffs, to demand further protection for the cliff top and beach adjacent to the existing pumping station.

A £60 million upgrade of the existing sewage treatment works was rejected in March 2001 following a lengthy public inquiry between October 1999 and February 2000.

Prior to the public inquiry there were demonstrations by residents along the South Coast Road outside the works, demanding no expansion of the works.

The prospect of the expansion, which would have meant the beach at Telscombe being covered with a concrete platform, was thought to have been ditched when planning inspector Simon Gibbs ruled in March 2001 that the project should not be allowed as it was in an Area of Outstanding Natural Beauty.

When the proposed boundaries for the new South Downs National Park were published earlier this summer, the area surrounding the existing Portobello works had been left out.

Southern Water has admitted it made representations to the Countryside Agency asking for Telscombe Beach and the area surrounding its existing works to be left out on the grounds it did not meet the criteria for an Area of Outstanding Natural Beauty.

The water company, which needs to build a treatment works somewhere in the Brighton area to treat waste water to a higher standard before it is pumped into the sea, made similar representations regarding other sites near sewage treatment works within the boundaries of the proposed national park.

Dr Turner said: "There is bound to be concern that Portobello could be on the cards again following the proposal that land nearby should no longer be protected as an Area of Outstanding Beauty. We have now got to get it back in and included in the new national park."

Telscombe town, district and county councillor David Neighbour said: "There has got to be all party support to get this piece of land back in the boundaries of the park to protect the area from development. One of the main reasons the expansion of Portobello was rejected was because it was in an Area of Outstanding Natural Beauty."

Jean Talbot, secretary for the Campaign for Residents Against Portobello, said: "We have reformed CRAP to fight any further plans for expansion. Our first priority is to get that piece of land back inside the boundaries of the National Park."

A spokeswoman for Southern Water said no plans had been submitted to expand Portobello and project engineers were still looking for sites to build a sewage treatment works for the Brighton area.