This paper takes as a given the need for accelerated progress towards an energy efficient, low carbon economy in response to increasingly powerful climate change and energy supply drivers which are beginning to have a global impact. It argues that markets have huge power to transform themselves but their "will" to do so is heavily conditioned by the nature, magnitude and duration of the value ... [Show full abstract] which is perceived, won or lost by those involved in and impacted by that transformation. For energy efficiency and low carbon technologies, there is a gap between the perception of their value by individuals and by society. So far as mitigating (and adapting to) climate change is concerned, there is a global imperative to achieve the societal good of a low carbon economy. The more time we spend not making the transition, the harder it will be for future generations and the more disruptive will be the climate change induced conditions they will face. Many Governments have recognised this imperative and have devised a range of regulatory, fiscal and market interventions to tackle and mitigate climate change. Ever since the Rio Summit in 1992, the UK Government has been among the leading protagonists for action. Its first climate change programme, launched in November 2000, featured new policies and measures designed to achieve reductions in our carbon dioxide emissions. A novel, groundbreaking element in the UK's climate change programme is the Carbon Trust - an independent, business led, Government backed company set up in March 2001. The Carbon Trust's objective is "to accelerate the transition to a low carbon economy by helping organisations reduce their carbon emissions and develop commercial low carbon technologies".This paper discusses low carbon technology innovation and commercialisation. It describes the Carbon Trust's roles: (a) to reduce carbon emissions now, using today's know how; (b) to help develop and commercialise new and emerging energy efficiency and low c- - arbon technologies; and (c) to understand the impacts of climate change and help inform the development of Governmental and corporate policies and measures to accelerate the transition to a low carbon economy. It also discusses the nature of innovation and commercialisation; how the Carbon Trust is working to understand it better; and how we have gone about applying our understanding in practice.