Two of the world's leading energy companies have stepped in to save a proposed giant wind farm off the Thanet coast.

E.ON and DONG Energy have become 50-50 partners in the £1.5billion London Array scheme, which was blown off course in May when Shell announced it was pulling out.

The two firms have now bought Shell’s stake in the project for an undisclosed sum.

The first phase should be completed by 2012, subject to a number of important contracts, such as those for the wind turbines, being secured.

Dr Paul Golby, chief executive of E.ON UK, said: "We believe that offshore schemes such as this have an important part to play as we look to ensure security of supply for the UK, reduce carbon emissions and keep energy as affordable as possible for our customers."

John Hutton, Secretary of State for Energy, added: "This exciting project will play an important role in our ambition to dramatically increase the amount of energy we get from renewable sources by providing clean, green energy from our own shores."

South Thanet MP Dr Stephen Ladyman has described the decision by E.ON and DONG to proceed with the London Array wind farm as "great news for the planet and great news for Thanet".

He added: "London Array could produce enough clean energy to supply a substantial part of London and the south east and a significant number of jobs in east Kent.

"Personally, I am still very angry about Shell's decision."

More than 270 turbines are planned for the Thames Estuary under the London Array scheme.

The Danish-made structures would be installed 12 miles off the Thanet coast and provide enough energy to supply a quarter of London’s domestic energy or the whole of Kent and East Sussex.

The turbines would be as high as the London Eye, with each blade as long as the single wing of a jumbo jet.