Deep sea mining, the new gold rush?

Researchers say rich metals deposits locked in the seabed 5km below the surface have huge industrial potential, but environmentalists warn against rushing to mine deep ocean trenches.

A British company has announced a major new project to mine the floor of the Pacific Ocean.

The UK arm of Lockheed Martin will be extracting rocks rich in gold, copper and other minerals four thousand metres below the surface, in an area twice the size of Wales.

It's controversial with environmental groups expressing concern that sensitive marine life will be destroyed.

BBC science editor David Shukman explains, undersea mining could become a new gold rush.