A proposal to erect, remove and then re-erect agricultural polytunnels on a 307 hectare site had been granted planning permission by Hertfordshire District Council. The site was within an AONB and close to a European designated site (SAC). The council had come to the conclusion that an environmental impact assessment was not required because the site comprised previously cultivated land. The planning permission was challenged in R (oao Wye Valley Association Limited) v Herefordshire D C. The court held that the council had been wrong in two ways. First, it was possible for previously cultivated land to fall within the "semi-natural area" definition. The site formed part of a high quality natural environment, notwithstanding previous human interventions. Second, the council was wrong in not concluding that the proposed development represented a significant intensification of the existing agricultural use. Thus EIA had been required and the planning permission was quashed. This decision is likely to have wide implications for intensive agricultural activities.