The London Energy Transformation Initiative (LETI) is a network of over 150 built environment professionals that are working together to put London on the path to a zero carbon future. The voluntary group is made up of developers, engineers, housing associations, architects, planners, academics, sustainability professionals, contractors and facilities managers, with support and input provided by the GLA and London boroughs. Elementa Consulting have initiated and coordinated LETI as they were frustrated that the current energy policy in London wasn’t driving design solutions that encouraged long term carbon emissions reduction. LETI was established to work collaboratively to put together evidence-based recommendations for two pieces of policy – the new London Environment Strategy and the rewrite of the London Plan.