The Court of Appeal decision in Turner v Secretary of State for Communities and Local Government shows that the concept of penness of the green belt' is not narrowly limited to an approach based on a measurement of volume.
Paragraph 89 of the National Planning Policy Framework (NPPF) offers exceptions to the general rule that inappropriate development is harmful to the green belt. One is: ‘Limited infilling or the partial or complete redevelopment of previously developed sites (brownfield land), whether redundant or in continuing use … which would not have a greater impact on the openness of the green belt and the purpose of including land within it than the existing development.’
Turner had applied for planning permission to redevelop green belt land to replace a mobile home and storage yard. Since the volume of the proposed development was less than that of the old development, Turner argued that the scheme would not have a greater impact on the openness of the green belt.
The court said the concept of ‘openness of the green belt’ was not limited to the volumetric approach; the word ‘openness’ was open-textured and many factors were capable of being relevant. Factors relevant to how built up the green belt was and would be if redeveloped were by no means the only ones. The inspector’s assessment of impact on the openness of the green belt had been a matter of evaluative assessment in the context of making a planning judgment. He had been entitled to take into account the difference in the visual intrusion on the openness of the green belt.