The Merton Rule may be the only mechanism left in place that could be used to help offset the onslaught of backtracking policies currently being rained down on the green building movement by the present UK government. The Merton Rule is so named after the Local Authority that in 2003 adopted the first prescriptive planning policy in the UK that required new commercial buildings over 1,000 square meters to generate at least 10% of their energy needs using on site equipment powered by renewable energy (sun, wind or water).