New farmland is set to be created in Tilbury thanks to thousands of tonnes of excavated land from London.

Tunnelling to extend London Underground's Northern line will begin in March, Sadiq Khan, London's mayor, has announced.

A pair of two-mile long tunnels will be created to bring the network to Battersea, in the south of the capital.

The £1.2 billion project is the first major expansion of the Tube since the Jubilee line in the late 1990s.

Two new stations will be opened in 2020 - one at the heart of the Battersea Power Station redevelopment and another at Nine Elms, serving developments such as the US Embassy and the revamped New Covent Garden Market, as well as existing communities.

Two 650-tonne tunnel boring machines were unveiled. When fully constructed below ground, they will each be 100 metres (328ft) long.

The machines will operate at depths of 26 metres (85ft) for six months, excavating more than 300,000 tonnes of earth.

This will then be passed along conveyors before being loaded onto barges and taken to Goshems Farm in East Tilbury, where it will be used to create arable farmland.

Transport for London say this will remove the need for more than 40,000 lorry journeys from the capital's roads.