'Sinking sand' warning after cliff collapses in Norfolk
The coastguard warned of "sinking sand" after a large section of cliff collapsed on to a beach.
Pictures posted on social media on Thursday afternoon showed the aftermath at Happisburgh, near North Walsham, Norfolk.
HM Coastguard Bacton said: "Please be aware the cliff is very unstable and the mud washing on to the beach can act like sinking sand."
It urged people to take care and to report any dangers on the coast by calling 999.