The project at Scroby Sands near Great Yarmouth will provide electricity for some 50,000 homes and be one of the largest offshore windfarms in the world.

Energy minister Brian Wilson announced on Wednesday the government would give £10m each to the Norfolk scheme and another of a similar size off the North Wales coast.

The two projects are the first of 18 proposed offshore plants unveiled in April to be given final approval by the government.

The scheme is to get £10m of government money

They are part of the government's plan to triple the amount of energy generated from renewable sources by 2010.

The Norfolk scheme will be operated by Powergen, which already runs the UK's first offshore windfarm off the Northumberland coast.

It is designed to generate 80 megawatts of electricity a year and is expected to cost £78 million.

Work could begin onshore by the end of the year, while construction out at sea is due to start by the spring.

The turbines will be 100m high and placed on a sandbank in the North Sea.

Natural resources

Mr Wilson said: "These developments are a major step forward for the UK offshore wind industry, and the clearest signal yet that UK manufacturing can play its part in the growing market for sustainable energy at home and abroad.

"There has never been production of renewable technologies on such a scale on British soil before.

"North Wales and Norfolk are blessed with some of the finest energy-rich natural resources in the world."

Last week, approval was given for the building of a second turbine at Swaffham in Norfolk.