A 50m-long crack has appeared in the cliffs at Mappleton beach in East Yorkshire raising concerns over the collapsing coastline.
The expanding crack and eroding coastline has led the council to cordon off the area while ground investigations are underway.
Speaking to BBC online, coastguard rescue officer and geologist Daniel Escreet said: “It’s a huge danger. It’s continuously slipping, it’s a landslip in action.
“It’ll be moving very slowly at the moment. But it could move very quickly at any time.”
A spokesperson for East Riding and Yorkshire Council said: “Coastal engineers and foreshores officers have assessed the situation and the decision has been taken to cordon off the area on the cliff top on the grounds of health and safety.
“The council is advising residents and visitors to the area to avoid the section of cliff top and the beach below while investigations and safety works take place.”