The authority's supplementary planning guidance (SPG) indicated that extensions leading to a cumulative percentage increase of no more than 25 per cent would have a reasonable chance of success. However, it had cancelled the SPG due to the introduction of the amended GPDO, which rendered its main points obsolete.
The council calculated that under the amended GPDO, it might be possible to extend the detached house by 60 per cent. However, it insisted that this did not prevent the exercise of control powers to stop disproportionate extensions where permission was required. The inspector sympathised with this view, opining that the existence of permitted development rights did not necessarily mean that they would or could in practice be exercised.
He referred to PPG2's advice that limited home extensions would not be inappropriate in the green belt and its guidance on what should be considered disproportionate. He took the view that the proposed 45 per cent increase on the original dwelling size would amount to inappropriate development.
DCS Number 100-064-480
Inspector Bob Marshall; Hearing