Largest ever robot fleet will map the UK's oceans

British scientists are hoping robots will be able to give the most detailed picture yet of life deep below the waterline.

The largest ever fleet of robotic submarines is setting of from the Isles of Scilly to explore the ocean depths.

The unmanned boats and submarines will travel 500km (300 miles) across an area off the southwestern tip of the UK.

The aim is to test new technologies and to map marine life in this key fishing ground.

The BBC's Science Editor David Shukman reports.