Waves up to 80ft high slammed into Britain when the monstrous Storegga landslides last struck, permanently changing the shape of Britain.
The 180-mile long collapse unleashed a barrage of 3,500 cubic kilometres of debris, shifting an area the size of Scotland into the crushing depths.
It caused a roaring tsunami that some say created the North Sea, drowning huge swathes of land – and now climate change could bring a second collapse.
The warning comes after world leaders were urged that drastic action was needed to stop melting Antarctic ice sending sea levels surging.