The Government's chief wildlife watchdog has called for a public inquiry into council plans to stop rocks falling from a unique stretch of cliffs.

English Nature has now urged Deputy Prime Minister John Prescott to intervene after a year of talks with Brighton and Hove City Council failed to find a compromise.

The council wants to fit rock bolts and wire mesh to cliffs at Black Rock, Brighton, to stop rock falls which have forced the closure of the popular Undercliff Walk.

Councillors gave themselves planning permission for the stabilisation work last year because of safety fears despite objections from the watchdog.

English Nature said the cliffs, protected as a site of special scientific interest and studied by scientists and students, could be "irreparably damaged" by the work.

A spokeswoman said the area's geology was unique and the history of rock falls had been well known when the Undercliff Walk was built.

She said: "Black Rock is an important part of the history and heritage of Brighton.

"A solution which accommodates a safe footpath away from this small stretch of cliff and retains this important part of our ancient geological heritage would appear to meet the needs of both interests."

The famous raised beach section of cliffs, behind Brighton marina, comprises several different rock types and cuts through a fossilised coastline, showing the shore, pebbly beach and cliffs from some 200,000 years ago.

The watchdog angered environment groups when it agreed to council plans to stabilise another section of the cliff, immediately to the east of Black Rock.

Phil Belden, of the Brighton Urban Wildlife Group, said neither the council or the watchdog had not done enough to protect the whole site.

He said: "It is profoundly depressing it has come to this when common sense should have prevailed a long time ago, before the bulldozers moved in."

Councils face stiff penalties for not protecting sites such as the Black Rock cliffs under the three-year-old Countryside and Rights of Way Act.

The council is also improving sea defences between the marina and Ovingdean while the Undercliff Walk, built in the Thirties, is closed.