Not only is this a successful implementation of a flagship pre-election green pledge to reduce emissions by 10% but it has also resulted in a saving of £13 million from energy bills.

Having achieved this target, Whitehall has now pledged to go even further by setting a target of cutting carbon emission by 25% by 2015.

On announcing the news, David Cameron said:

"A 13.8% cut in emissions in just one year is a great result and the civil service should be very proud of this achievement.

"But to be the greenest government ever we need to do more to stamp out energy waste in Whitehall, and make it easier for people and business to use energy more efficiently. That's why I'm committing the Government to go further by reducing emissions by 25% by 2015"