This case concerned a challenge to Kensington and Chelsea’s policy on basement development, brought under s. 113 of the Planning and Compensation Act 2004. Adopted in response to concerns about impacts of the significant increase in the amount of basement development on the amenity of neighbours, the policy imposes strict limits on the depth and lateral extent of basements which will be permitted.
The Claimants’ challenged was brought on two principal grounds. First, the Claimants contended that, in adopting the policy, the Council had failed to consider its effect on the take up of permitted development rights to construct basement extensions to dwelling houses. In particular, by severely restricting the size of basements for which planning permission would be given, the policy would simply encourage the construction of basements under permitted development rights to which the limits on depth do not apply, in circumstances where there would be no conditions to ensure that the construction did not affect the amenity of neighbours. In support of the argument the Claimants pointed out that, while the Council did not intend to make an Article 4 direction before adopting the policy, this very consideration had, shortly after the policy was adopted, led it to make a Borough wide Article 4 direction removing those rights. If the Article 4 direction is confirmed, and assuming the Secretary of State does not intervene, it will take effect in 2016.
Mrs Justice Lang rejected this argument, on the basis that the Council had been aware of permitted development rights throughout, and had previously considered making an Article 4 Direction, but had said that the take-up of such rights would be monitored. In her judgment, “the Defendant simply took a different approach to the benefits of the Basements Planning Policy, even taking account of the potential problem with permitted development rights”.
Under the second ground, the Claimants argued that the Sustainability Appraisal (incorporating its Strategic Environmental Assessment obligation) was flawed for a failure to assess a reasonable alternative to the Council’s preferred policy. This argument was also dismissed. Following the Court of Appeal’s decision in Ashdown Forest Development Ltd v Wealden DC  EWCA Civ 681 (which was handed down the day after argument in the RBKC challenge had concluded) the judge concluded that the question what is a reasonable alternative is a matter of evaluative judgment for the authority in question.
Paul Brown QC acted for the Claimants.
A copy of the Judgment can be found here.