Deep sea corals have been seriously harmed by the Deepwater Horizon oil spill, scientists have said.

A survey of one site near BP's Macondo well in the Gulf of Mexico uncovered "compelling evidence" of pollution damage.

Coral communities more than 4000ft below the surface of the ocean appeared stressed and discoloured.

Tests showed that oil from the site bore Deepwater Horizon's chemical "fingerprint".

The explosion and blow-out in April 2010 poured an estimated 160 million gallons of oil into the Gulf.

US scientists used an automated submersible, Sentry, and a manned robotic armed vehicle, Alvin, to obtain images and samples at a depth of 4300ft.