Rock falls are on the increase

Police say they do not know how much rock has fallen, but they described the fall as "substantial".

Eyewitnesses suggested a 30 to 40-metre stretch of the cliff collapsed.

The Sidmouth lifeboat and two coastguard units helped police search for possible casualties in the rubble.

A spokeswoman for Portland coastguards said there were people on the beach at the time, but none was in the immediate vicinity of the collapse.

Warning signs

A police spokesman said: "We believe no-one was in the immediate area at the time and as far as we can tell no one has been injured."

Warning signs have been put up near the beach and East Devon District Council has been informed.

It is not a cliff to stand underneath

Dr Raymues Gallois, geologist

This is the latest in a series of rock falls and landslips around the country.

Heavy rain over the past two years is being blamed.

The water can soak into the rock increasing pressure and leading to sudden collapses.

It can be more dramatic along the coast where the sea has made the cliffs steeper.

Wet weather

Professor Martin Culshaw from the British Geological Survey (BGS) told BBC News Online: "It appears to us there have been considerably more falls on the coast and lanslips inland in recent years.

"This is directly attributable to the last year or so being the wettest period on record"

Dr Raymues Gallois, who has studied the coast in Devon, said there had been particular problems at Salcombe Hill Cliff and a number of falls.

"It is not a cliff to stand underneath," he said.