An engineering expert told a public inquiry he believes building a long chalk sea-defence wall to protect crumbling cliffs will not ruin the coastline.

Residents who live in Crangon Cottages, perched on the edge of crumbling cliffs at Birling Gap, near Eastbourne, nodded in agreement as Brian Waters gave evidence.

The residents are backing plans for a sea defence scheme to slow down erosion and save their cottages from falling into the sea.

Landowners National Trust and English Nature are opposed to the sea wall, called a revetment, arguing nature should be allowed to take its course.

Speaking on the third day of the inquiry, the independent engineering consultant disputed evidence given by engineer Ian Townend for the National Trust.

On the first day of the inquiry, Mr Townend had insisted the barrier would only reduce erosion by a small degree.

However, Mr Water said: "The evidence given by Mr Townend was an overly simplistic way of calculating erosion on this cliff face.

"He was peering into a glass darkly. You have to take a lot of factors into consideration when estimating the rate of erosion.

"Global warming may cause more frequent storms, resulting in the coastline crumbling faster than anticipated. In 30 years we will know the answer."

Wealden District Council blocked an initial plan from resident Jean Fawbert and the Birling Gap Cliff Protection Association for a 138-metre sea defence but later agreed to a shorter 30-metre wall.

Without the defences, it is estimated the six cottages and a hotel will be lost to the sea within the next 20 years.

The case was called in by Environment Secretary John Prescott, who will decide which plan, if either, will be allowed.

Representatives from each party involved, along with the Government inspector ruling on the case, are due to visit the stretch of coastline to look at the cliff face and shingle levels on the beach.

The hearing is expected to run for another five days.