GIANT wind turbines the size of London's Big Ben clock tower are coming to the North-East.

The four windmills, standing 100 metres tall, will be the biggest and most powerful to be built on the UK mainland.

They will be erected on two remote sites in County Durham - two on Holmside Hall Farm, at Craghead, near Stanley, and two at Crows-house Moor, south of Harehill Farm, Haswell, near Durham.

They will provide enough electricity to power 4,500 homes, reducing carbon emissions by 9,000 tonnes a year.

The investment, by energy company Powergen, is part of the Government's drive to generate more power from renewable sources, such as wind, water and wood.

Powergen Renewables said it hoped to start work at Holmside and Harehill in late summer or early autumn, and expected the turbines to be generating electricity early next year.

A spokeswoman said: "These 2.75megawatt turbines will stand about 100m to tip height, roughly the same height as Big Ben, and will be the biggest and most powerful on the UK mainland so far.

"They have been designed to have as little impact on the environment as possible and will be painted in muted colours to blend in with the background."

Durham City Council and Derwentside District Council granted planning permission for the two sites in 2000, with very little local opposition.

The turbines are part of a £120m programme to boost renewable energy production.

Powergen has also signed an option for lease for a wood-burning power station at Lockerbie, in Scotland, an off-shore wind farm off the coast of Great Yarmouth, and hydro power stations at Rannoch, Perth, and Kinross and Garbat, in the Scottish Highlands.

The company already has 16 wind farms, producing enough power to supply 82,000 homes.

The new projects aim to increase the company's renewable capacity by 1,000MW by 2010.