Scientists have discovered the largest single coral ever recorded – so big that they had originally thought it was a long-forgotten shipwreck.

The “mega coral” – which is a network of small creatures that together form one huge organism rather than a reef – was found near the Solomon Islands in the South Pacific.

Unlike coral reefs around the world that have been struck by bleaching as a result of warming seas, the newly discovered coral is in rude health.

Measuring 112ft by 105ft and 16ft high, it is longer than a blue whale and amounts to the size of five tennis courts.

The vast coral, thought to be 300 years old, was discovered by marine scientists on the National Geographic’s Pristine Seas expedition in the Three Sisters Islands, hundreds of miles south-east of the capital, Honiara.