The world’s biggest iceberg – more than twice the size of Greater London – is on the move. After a few weeks loitering on the fringes of Antarctica, it’s begun to drift at pace once more.

An image of the A23a iceberg taken by the Copernicus Sentinel-3 satellite

A23a, as it’s known, broke away from the Antarctic coastline way back in 1986, but it’s only recently begun a big migration.

For more than 30 years, it was stuck rigidly in the bottom-muds of the Weddell Sea like a static “ice island”. A 350m-deep keel had anchored it in place.