World's biggest iceberg spins around

Like a dainty ballerina, the world's biggest iceberg has just completed a perfect pirouette.

The near-trillion-tonne frozen block, A23a, began its spin at the beginning of the year, while holding broadly the same position just north of the Antarctic Peninsula.

The berg is expected shortly to step into a powerful current that will sweep it away into the Southern Ocean.

A23a covers an area more than twice that of Greater London.

Video courtesy Nasa/Modis/BAS