Deep deep down

The UK's deepest-diving robot submarine has successfully completed its first mission, in the Atlantic Ocean.

The mission formed part of a research expedition investigating potential threats from tsunamis, giant landslides and earthquakes to coastal communities along the west-European margin.

The Autosub6000 was developed by British engineers and can dive to a depth of 6,000 metres - nearly four miles. An Autonomous Underwater Vehicle (AUV), the Autosub6000 is not controlled from the surface and is pre-programmed before each mission.

For its first scientific mission, Autosub6000 was released from the research vessel RRS James Cook and sent almost three miles below the surface to investigate a submarine canyon north of the Canary Islands.

Upon its return to the surface, some 24 hours later, the vehicle provided scientists with spectacular 3D images showing holes in the seafloor the size of a football stadium.