Residents and holidaymakers are being urged to stay away from the cliffs as hot temperatures make them even more unstable.

As the temperatures are set to increase over the weekend, Dorset Council is appealing to people visiting its beaches to take extra precautions due to an increased risk of rock falls.

In extreme temperatures, the risk of rockfalls along Dorset's World Heritage coastline is even greater than usual. Heat causes rocks to expand and, particularly during temperature fluctuations, any pre-existing cracks can widen, and new cracks can also form. This makes cliffs potentially more unstable and rockfalls more likely to happen.

Dorset and East Devon's Jurassic Coast is famous for its dramatic coastline, which is constantly eroding and moving. As the rocks crumble and fall, they can expose fossils, which gives us a fascinating look back in time, and is why the coastline is recognised as a World Heritage Site. This erosion process can be devastating if people are sat underneath them.

Councillor Ray Bryan, portfolio holder for highways, travel and environment, said: "Rockfalls are entirely unpredictable and can happen at any time, but we do know which conditions make them more likely, and prolonged hot and dry spells are one of them.

"We would encourage anyone thinking of visiting the Dorset coast during this heatwave to stay away from the base of cliffs, and if you are walking along the coast paths, keep well away from the edges. Never ignore a warning sign - they are there for your safety.

"It is easy to enjoy the spectacular and fascinating Jurassic Coast without putting yourself or others at risk."

Dorset's coastline has a number of areas with an increased potential for rockfalls, particularly on the cliffs around Seatown, Eype, Burton Bradstock, West Cliff, East Cliff, Mupe Bay, Lulworth and Swanage.

Catherine Pennington, landslide specialist at the British Geological Survey, said: "Landslides can occur on our dynamic coast at any time and the science research to fully understand the link between rockfalls and temperature fluctuations is still ongoing.

"What we do know is that cracks can form and widen during these changes in temperature. In general, cracks related to instability can be very difficult to see from the cliff top, as can unsupported, overhanging rocks, so, as well as staying well away from the cliffs on the beach, it is also important to stay away from the cliff edges at the top."