Currently, there are over 40GW of offshore wind farms at various stages of development, with over 4GW in construction or with planning consent.

The sector is set to provide 150+ TWh of carbon free electricity a year, compared to the UK’s total electricity consumption in 2009 of 374TWh, creating up to 70,000 ‘green collar’ jobs and attracting billions of pounds in investment.

Ed Miliband, secretary of state at Department of Energy Climate Change, said: “The UK is now the world leader in offshore wind energy generation. We are also set to be a center of manufacturing for offshore wind. We’re creating the right conditions and incentives to maximize the potential of our wind resource so we can create thousands of new jobs and generate our own home-grown, clean, secure energy.

”Labour is committed to maintaining the renewables obligation and reforming the planning system to build on this progress. We will also create the Green Investment Bank and maintain the Annual Investment Allowance to support our renewables industry.”

Simon Hughes, secretary of Liberal Democrat Shadow Energy and Climate Change, said: ”We are delighted to see the first gigawatt of installed wind energy capacity. It is an important milestone but we need to do much more if we are to cut carbon emissions and our reliance on fuel imported from abroad.

”Investing in infrastructure for a new green economy not only helps create jobs now but will allow Britain to take its place at the cutting edge of this growing industrial sector for the future.

”That’s why the Liberal Democrats have ambitious plans to invest GBP400m in our wind turbine manufacturing capacity. Britain clearly has the manufacturing and engineering expertise to lead the world in offshore wind, but the government has an important role in supporting this.”