Geologists are warning the public to be extra vigilant for signs of landslips following the recent tragedy in North Wales.

The Sussex cliffs are some of the most vulnerable in the country, with parts of the coastline falling into the sea.

During winter dangerous lumps fall without warning.

As the cliffs change shape, they could turn into killers similar to the tragedy which hit Nefyn, in North Wales, where a landslip killed an elderly woman.

This winter the number of cliff falls has increased. In the past month there have been falls at Brighton Marina and Ovingdean forcing Brighton and Hove Council to close the Undercliff Walk. There was also a fall at Telscombe Cliffs, leaving fencing dangling over the 80ft cliffs.

Walkers have commented about the large amount of fallen chalk on lower promenades and beaches loosened by the wet autumn.

In the next two decades, further falls could bring homes south of the main A259 South Coast road closer to the cliff edge and the sections of the road hugging parts of Beachy Head may disappear into the sea.

If someone had been walking under the cliffs at the Marina, Ovingdean or Telscombe they would have been injured or killed as the rocks came down.

More than 69,000 homes and 7,000 businesses are at risk from coastal erosion in Britain with more than £7 billion pounds worth of property at risk.

The cost of protecting them is enormous and the Government is taking the view that in some areas nature must take its course.

An experiment to protect inland cliffs at Lewes using fine netting, resulted in birds dying after becoming trapped.

At the Birling Gap Inquiry last year environmentalists warned the proposed sea defences at the remote spot between Seaford and Eastbourne would cause untold damage to the coastline, while locals demanded coastal defences to protect their homes.

The result of the inquiry is expected by Spring.

Elliot Morley, the Government minister responsible for England's coastline says: "We cannot simply go on building higher and higher walls in the face of rising sea levels."

Jakki Skipper, a cliff expert from the Natural History Museum believes more attention should be paid to protecting the cliffs and to where councils give permission for development. She is particularly concerned about cliffs at Newhaven Heights where excavations have been made into sediments formed over 55 million years ago.

She said: "I am extremely concerned the current excavations will increase the likelihood of a major, seaward landslide, and also create new routes for water that will cause landslides in a landward direction."

If the early sign of a landslip or cliff fall is seen that threatens a public road or footpath, it should be reported to the local authority's highways engineering or technical services departments. If it is on private property, owners should seek further advice from insurers and possibly a chartered engineering geologist or geotechnical engineer.

Councils of all levels are responsible for the maintenance of cliffs in their areas. There is back-up advice available from experts and environmental organisations, such as English Nature. The Environment Agency is responsible for areas where there is a risk of coastal flooding.

Bob Edgar, English Nature's Conservation Officer for Sussex, says the recent cliff falls have been the result of water getting into the fine fissures of the chalk, freezing and then expanding, loosening chalk.

He said:"I am amazed at the number of people that calmly walk underneath the cliffs, unaware of any danger. Falling cliffs are not always a bad thing. It does build up the sea defences."

A large fall at Beachy Head when thousands of tons fell 500ft on to the beach happened two years ago this weekend. Fifty feet of the cliffs fell away.

Further rainfalls could lead to more cliffs falls. No longer can beautiful cliffs be regarded as solid as a rock.