Cliff walkers in Dorset have been urged to take extra caution after a big landslide close to the popular Durdle Door beach.
There are no reported injuries after a 100m stretch of cliff at St Oswald's Bay fell into the sea.
It is believed to have occurred overnight, a coastguard told Sky News.
Nick Lonsdale, duty watch manager at MRCC Portland, said: "The landslide was first reported to us at 8am. To our knowledge, no one was harmed by it, but it is too early to speculate.
"We are making arrangements to divert the coastal path that was damaged by the landslide.
"We would urge walkers to observe signs and stay away from the edge, as tempting as it might be to look over the edge."
Dorset's jurassic coastline and picturesque cliff-top paths are popular tourist attractions.
Mr Lonsdale said it was not always possible to predict when a landslide would occur, or which sections of the coast were vulnerable.
"Along the UK's entire coastline, there are sections that will crumble and fall away, sometimes without warning of any sort," he said.