When Rupert Wingfield-Hayes visited the Spratly Islands in the South China Sea, he found Chinese fishermen were deliberately destroying coral reefs.

Poachers were revving the engines on their boats sending clouds of black diesel smoke pouring into the air - and under the water, were piles of shattered white coral branches.

As he reports, some of the fishermen were also catching massive giant clams, at least 1m across.