A UK trading scheme for greenhouse gas emissions could be ready to start as early as April 2001. This would put the UK at the forefront of negotiations for any subsequent worldwide trading scheme. The system is intended to ensure investment in energy efficiency occurs where it is most cost-effective. Under the scheme, companies would agree emissions targets with the Government. Firms which could exceed their target cost-effectively would be able to sell permits for their surplus allocation to others. `Companies would be able to plan over a longer period – you would know your allocation so you would be able to say: “We’ll buy permits for so many years and invest in energy efficiency for the period after that”,’ said Richard Jackson, senior policy adviser for the CBI.