It includes activities undertaken by companies across the whole environmental supply chain, from R&D, through manufacturing into distribution, retail, installation and maintenance services. Companies are included in the supply chain where 20% of their turnover is supplied into the LCEGS sector, but importantly only the sales activity relating to this sector is included in this study. This inclusion is akin to the way other sectors of the economy, such as aerospace, are measured. The study uses ‘bottom-up’ data based on what companies actually do, rather than what they are classified as doing under the SIC system.