Crossrail soil used in nature reserve

London's Crossrail is currently the biggest construction project in Europe, but it's not just building a transport link. The earth excavated from the capital is being used to create a reserve for wild birds in Essex, run by the RSPB.

Contractors have just delivered their one millionth tonne of soil to the location, making it the largest movement of earth out of central London since the Edwardian age, as Martin Stew explains.