Successful solutions can then be replicated elsewhere in the public sector.

Energy and Climate Change Minister Joan Ruddock said: “We know it’s important to show leadership in this area – if we want everyone else to retrofit their homes it’s important government buildings also get some treatment.

“Some of the money will go on energy efficiency, some on smart meters, some on low carbon cars, and some will go on mapping the possibilities of renewable energy on public land – that will be led by the Forestry Commission.”