The British Antarctic Survey has released footage of the chasm along which a 1,550 square kilometer iceberg "almost the size of Greater London" broke off from the Brunt Ice Shelf. Cracks in the 150-meter-thick ice have been developing for several years, and the final break occurred on January 22 during a spring tide. According to the surveyors, calving is a natural event on the ice shelf and is not directly linked to climate change.