Video footage shows how cracks began forming a few years ago
A big iceberg nearly the size of Greater London has broken away from the Brunt Ice Shelf in Antarctica.
Dramatic images reveal a vast expanse of ice measuring 600 square miles in what researchers say is the second major break-off in the area in the last two years.
But the British Antarctic Survey said there was nothing - or almost nothing - to worry about because the phenomenon was normal and not caused by climate change.
"Some of the ice shelves that are broken up in more northerly locations are the result of climate change. But this one is further south," Professor Dominic Hodgson, a glaciologist for the British Antarctic Survey explained.
"And it's worse. It's well below freezing there," he added.
"So it's not linked to any changes in atmospheric or ocean temperatures. The reason it's important, it's a very large calving event for Antarctica.
"We do see these sort of calving events periodically and also the ice shelf - our station was situated on the piece of ice shelf that has broken away.
"So had we not moved it several years ago, we would have been in a situation now where we have a station floating off," he explained.
The iceberg was not likely to dramatically affect sea levels, researchers said, and it will be named by officials at the US National Ice Centre.
"It's on the edge of the Antarctic ice sheet where the ice sheet goes off the land and then extends out into the sea,” says Professor Dominic Hodgson added.
"We had some communication from our remote instruments on the ice shelf informing us that part of the ice shelf approximately the size of Greater London calved off."
Want a quick and expert briefing on the biggest news stories? Listen to our latest podcasts to find out What You Need To Know…