The milestone in installed wind energy capacity was broken by the final commissioning of three wind farms - the EDF Energy Renewables 38 MW Longpark, Scottish Power Renewables 30 MW Dun Law extension and the first phase of Dong Energy's 173 MW Gunfleet Sands offshore wind farm, BWEA said.

The UK is currently gearing up to reach the Renewable Energy Strategy target of 30 GW of wind energy by 2020. There are over 12 GW of wind schemes either operational, being built or already with planning permission. When this pipeline of projects is built out in 2012, wind energy could overtake nuclear in installed capacity, according to BWEA.

With another 9 GW worth of schemes in planning waiting for approval there are now over 20 GW of wind at one stage or another of the development cycle. However, onshore approvals by local councils have now fallen to a new low, with just 25% of applications being approved.

Adam Bruce, BWEA Chairman, says: "The delivery of the 4th GW of wind energy, in the teeth of the UK's worst recession in a generation, is an indication of the maturity and resilience of our sector.