The London Array wind farm in the outer Thames Estuary is currently the largest in the world

A Cumbrian wind farm is set to become the largest in the world, with plans being drawn up to double its size.

The £1.2 billion Walney offshore wind farm opened last year with 102 turbines in the Irish Sea, nine miles from land. The proposed extension by the Danish company Dong would make it twice the size and provide electricity for 559,000 homes.

The London Array wind farm in the outer Thames Estuary is currently the largest in the world, with 175 turbines, enough to power 470,000 homes.

The planning application is due to be submitted in May and if it is accepted by the Planning Inspectorate, the 144 sq km extension could be operational by spring 2018.

Cliff Pullen, project manager for the wind