<p>In 1990, the Conservative Government published a White Paper on the environment, This Common Inheritance (HMSO, 1990). It summarised the achievements of the past, and advanced the concept of integrated pollution control (IPC). In place of the separate regulation of air, land and water pollution, the new approach would take account of the impact of emissions on all aspects of the environment. The inevitable trade-off required an integrated solution-termed the Best Practical Environmental Option (BPEO). The White Paper went further. It suggested how this integrated pollution control was to be applied. Regulators would calculate the Best Available calculation, set an authorisation or consent, a maximum level of emissions.</p>