The world’s largest and oldest iceberg is on a collision course with a British island, raising fears that its colonies of penguins and seals could be wiped out.

The mega-iceberg, known as A23a, is twice the size of Greater London and broke off the Filchner Ice Shelf in Antarctica in 1986 before running aground for 30 years.

It became dislodged from the seafloor in 2020 and began drifting northwards until it was trapped in a swirling ocean vortex in 2024. It has now been slingshotted in the direction of the British overseas territory of South Georgia.

It is 173 miles away from the island and is expected to make contact in two to four weeks, depending on the currents.