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On board Norway's giant underwater gas platform

5 August 2013 Last updated at 10:49 BST

A structure the size of a football pitch has been sent plunging to the bottom of the ocean, 125 miles off the coast of Norway.

It will house a giant compressor claimed to be the world’s biggest offshore machine.

The Statoil equipment has been designed to pump some £20bn ($30bn/23bn euros) worth of gas from a depleted gas field.

It is a technological leap for Statoil to place the compressor on the sea bed instead of on a typical platform perched above the waves.

Roger Harrabin got a view from the compressor platform before it was sunk.